Online Political Microtargeting : Promises and Threats for Democracy

Political campaigns are increasingly combining data-driven voter research with personalised political advertising: online political microtargeting.1 Through political microtargeting, a political party can identify the individual voters which it is most likely to convince. Additionally, a party can match its message to the specific interests and vulnerabilities of these voters. Modern online marketing techniques promise to make microtargeting even more tailored to individual voters, and more effective. These techniques are primarily used in the United States, but have recently gained popularity in European countries too. Several parties in European countries are looking into the possibilities of microtargeting. Online political microtargeting is a type of personalised communication that involves collecting information about people, and using that information to show them targeted political advertisements. Politicians apply microtargeting because they expect that targeting makes ads more effective. Such ads can address issues which are important to an individual, adapting the format and language to meet the individual needs and interests for maximum effect. Recipients of targeted political information are more likely to act upon it. Online political microtargeting may be both a blessing and a curse to democracies. It could increase participation, and lead to more knowledge among voters about certain topics. But microtargeting also brings risks. For instance, a political party could, misleadingly, present itself as a one-issue party to different individuals. And data collection for microtargeting raises privacy concerns. This paper focuses on the following questions: what is online political microtargeting, and what are its promises and threats? This paper combines insights from both a legal and social science perspective. We focus mostly on European countries and the US. Section 2 introduces the practice of online political microtargeting. Section 3 discusses the promises of online political microtargeting, and Section 4 the threats. Section 5 discusses why the threats, while serious, should not be overstated. Section 6 explores how policymakers in European countries could intervene, and sketches some problems they would encounter if they wanted to intervene. Section 7 concludes: we call for more research and debate about online political microtargeting.


Introduction
Political campaigns are increasingly combining data-driven voter research with personalised political advertising: online political microtargeting. 1 Through political microtargeting, a political party can identify the individual voters which it is most likely to convince.Additionally, a party can match its message to the specific interests and vulnerabilities of these voters.Modern online marketing techniques promise to make microtargeting even more tailored to individual voters, and more effective.These techniques are primarily used in the United States, but have recently gained popularity in European countries too.Several parties in European countries are looking into the possibilities of microtargeting.
Online political microtargeting is a type of personalised communication that involves collecting information about people, and using that information to show them targeted political advertisements.Politicians apply microtargeting because they expect that targeting makes ads more effective.Such ads can address issues which are important to an individual, adapting the format and language to meet the individual needs and interests for maximum effect.Recipients of targeted political information are more likely to act upon it.Online political microtargeting may be both a blessing and a curse to democracies.It could increase participation, and lead to more knowledge among voters about certain topics.But microtargeting also brings risks.For instance, a political party could, misleadingly, present itself as a one-issue party to different individuals.And data collection for microtargeting raises privacy concerns.
This paper focuses on the following questions: what is online political microtargeting, and what are its promises and threats?This paper combines insights from both a legal and social science perspective.We focus mostly on European countries and the US.Section 2 introduces the practice of online political microtargeting.Section 3 discusses the promises of online political microtargeting, and Section 4 the threats.Section 5 discusses why the threats, while serious, should not be overstated.Section 6 explores how policymakers in European countries could intervene, and sketches some problems they would encounter if they wanted to intervene.Section 7 concludes: we call for more research and debate about online political microtargeting.

Online Political Microtargeting: Promises and Threats for Democracy
Utrecht Law Review | Volume 14 | Issue 1, 2018

Online political microtargeting
In this paper, we focus on online political microtargeting, a category of political microtargeting.Online political microtargeting involves 'creating finely honed messages targeted at narrow categories of voters' based on data analysis 'garnered from individuals' demographic characteristics and consumer and lifestyle habits'. 2 Online political microtargeting can take the 'form of political direct marketing in which political actors target personalized messages to individual voters by applying predictive modelling techniques to massive troves of voter data'. 3Online political microtargeting could also be seen as a type of behavioural advertising, namely political behavioural advertising.Behavioural advertising is a modern marketing technique that involves tracking people's online behaviour to use the collected information to display individually targeted advertisements. 4nline political microtargeting is used, for example, to identify voters who are likely to vote for a specific party and therefore can be targeted with mobilising messages.(For ease of reading, we also refer to 'microtargeting').Microtargeting also enables a political party to select policy stances that match the interests of the targeted voter -for instance family aid for families, or student benefits for students.

Online political microtargeting in the US
In the US, political microtargeting has developed in the context of offline canvassing. 5Yet, there has been a rise in data-driven campaigning and a sophistication of microtargeting that was unimaginable just a few decades ago.Political scientist Colin Bennett highlights four trends that can help to explain the rise in political microtargeting in the US: 'the move from voter management databases to integrated voter management platforms; the shift from mass-messaging to micro-targeting employing personal data from commercial data brokerage firms; the analysis of social media and the social graph; and the decentralization of data to local campaigns through mobile applications.' 6n the US, political parties and intermediaries hold extremely detailed information about possible voters. 7New methods of voter data collection and data analysis have improved and enriched traditional forms of political microtargeting like canvassing.But these possibilities have also enabled much more refined methods of online political marketing, which is the focus of this paper.
In the US, several companies offer online microtargeting services especially to politicians.For instance, companies like CampaignGrid and Cambridge Analytica enable politicians to target people with ads on Facebook, LinkedIn, and elsewhere on the web. 8Cambridge Analytica claims to have collected 'up to 5,000 data points on over 230 million American voters'. 9The company attempts to identify people's personality traits to predict what kind of message is most likely to persuade people. 10ith online microtargeting, political communications can be targeted at individuals or niche audiences, and the messages can be adapted to the recipients.A company gives an example of the possibilities for targeting niche audiences: 'targeting fathers aged 35-44 in Texas who frequent gun enthusiast websites'. 11he digital director of the Donald Trump campaign suggests that there is not much difference between behavioural targeting and online political microtargeting: 'It's the same shit we use in commercials, just has fancier names.'12

Online political microtargeting in European countries
Online political microtargeting is not yet widely deployed in European countries.However, it appears that political parties across Europe look to the practices in the US for inspiration.As Bennett notes, 'political parties elsewhere have reportedly looked with great envy on the activities of their U.S. counterparts and longed for similar abilities to find and target potential supporters and to ensure that they vote.' 13 Parties in the UK have been quick to emulate online political microtargeting campaigns. 14In the 2015 UK general elections, online political microtargeting helped the Conservative Party to secure key marginal constituencies and, thus, to win the elections. 15Three major parties in the UK, the Labour Party, the Conservative Party, and the Liberal Democrats, have invested in building voter databases, with the help of consulting services and data brokers. 16ome political parties in Western Europe have recruited US campaign strategists to professionalise election campaigns, in particular on the use of social media and online political microtargeting. 17To illustrate: the UK Conservatives hired Jim Messina, campaign advisor to Barack Obama, to set up microtargeting campaigns. 18The Dutch Green Party has hired the US-based digital strategy firm Blue State Digital. 19To sum up, microtargeting is becoming more widely used in Europe too.

Promises
We discuss some of the main promises and threats of online political microtargeting.We roughly distinguish promises and threats for citizens, political parties, and public opinion.

Citizens
Microtargeting could increase political participation and therefore strengthen democracy.Media in general, and social media in particular, can mobilise citizens in times of elections.Citizens may be mobilised to cast their vote on election day, attend a political event, or discuss politics with family members, friends and Online Political Microtargeting: Promises and Threats for Democracy Utrecht Law Review | Volume 14 | Issue 1, 2018 others.Moreover, media can increase citizens' political knowledge, and help citizens to make more informed voting choices. 20et, targeted online information could amplify the effects of campaigns on citizens for two reasons.First, microtargeting enables politicians to engage audiences through more relevant advertisements.As an American microtargeting company puts it: 'A positive aspect of relevant campaign ads is that the ads are more relevant to the voter receiving them: voters receive ads about issues they are most likely to care about, with easily accessed links to click-through to learn more.' 21 Traditional forms of advertising, such as television ads, reach a mass audience.But not the entire audience might be interested in such ads.Through microtargeting, specific audiences can be connected with specific agenda points of political parties.So microtargeting could lead to more relevant information or ads for specific audiences.
To illustrate: say Alice is a 20 year-old citizen and is not interested in politics.Yet Alice regularly checks her friends' Facebook updates.On Facebook, Alice receives a political ad that informs her about the viewpoints of a political party that targets younger citizens (e.g., pro-university funding).Because the political information concerns an issue that appeals to younger citizens, Alice decides to find more information about the party and its viewpoints.Thus, targeted political advertising encourages Alice to find more information, and perhaps to vote for this party.
There is a second reason why targeted political information can amplify the effects of campaigns.Online political microtargeting might reach citizens who are difficult to reach through mass media such as television.A challenge within democratic societies is to reach politically uninterested voters and mobilise them to participate in politics.Such citizens often opt out of traditional media exposure, such as watching television news and reading newspapers.It has been argued that those who tune out of news may not be informed about politics. 22owever, many of these citizens may use the internet, for instance for entertainment or social media. 23y targeting these uninterested citizens online, a political party could reach them, expose them to political information, and influence or persuade them.Such exposure increases the likelihood that citizens cast their vote or become more interested in politics.In this way, targeted political information may help to reach those who are difficult to reach in an offline environment.
In sum, online political microtargeting has possible advantages for citizens: it can reach citizens who ignore traditional media, and it can interest people in politics through tailored messages.Microtargeting might thus increase information, interest in politics, and electoral turnout.

Political parties
For political parties, three of the main promises of online political microtargeting are that it can be cheap, efficient, and effective.Some forms of online microtargeting can be relatively cheap for political parties.In Europe, national political parties and candidates use various social media platforms.Today, political communication routinely integrates social media 'to target messages, to recruit volunteers and donors and to track issue engagement'. 24Compared to television broadcasting, social media can offer cheaper means Balazs Bodo, Claes de Vreese Utrecht Law Review | Volume 14 | Issue 1, 2018 to communicate to a large audience. 25Social media thus offers an alternative for small and new parties that cannot afford expensive TV campaigns to reach potential voters. 26 first mover advantage could accrue to the political party first starting to use microtargeting.For instance, the UK Conservative Party focused their personalised political communications on motivating their supporters to vote in particular swing constituencies during the 2015 national elections. 27Small political campaigns on social media are a comparatively more agile form of political advertising and allow small political parties and newcomers to focus their efforts on likely supporters.This first mover advantage, however, lasts only until political competitors start using microtargeting too.
Microtargeting helps political parties to run a more efficient campaign.Instead of showing a broad range of people the same political advertisement on Facebook, campaigns can solely focus on their actual and potential constituencies.For example, a farmers' party can save money by only targeting people who live in rural areas, while ignoring obvious metropolitan users.

Public opinion
Regarding public opinion, microtargeting promises to increase the diversity of political campaigns, and voters' knowledge about certain issues.First, microtargeting could make political campaigns more diverse.In representative democracies, voters select political parties that they find suitable to form the government.During the election campaign, parties explain their political programme to the electorate to generate support.From a liberal perspective on democracy, election campaigns contribute to the marketplace of ideas. 28All parties offer their political ideas and priorities to the public who can then choose the party that best fits their political ideas, preferences, and priorities.However, a key problem for voters is that the number of parties, each with a political programme, is so large that voters are overloaded with information. 29Hence, voters choose to, metaphorically speaking, visit only a small number of market stands in the marketplace of ideas.Voters thus make their electoral decisions with limited information.
Microtargeting can expose voters to information that is most relevant for their voting decision.Many voters have specific interests in particular policy fields, for example immigration or education.With microtargeting, political parties can target voters with information within these preferred policy fields. 30Hence, voters can base their voting decision on the programme that convinces them the most about the issue they care about the most.This would not be possible in an exclusively mass-communicated information environment.Masscommunicated campaigns are usually limited to a small number of issues that are discussed extensively by all parties.Such niche topics are unlikely to be discussed during national mass-communication campaigns. 31icrotargeting could thus diversify political campaigns.Even though there is a smaller audience for each issue, more issues could be discussed during political campaigns.With microtargeting, topics which are only relevant to small audiences may get a market stand in the marketplace of ideas.
A potential benefit of microtargeting on public opinion is that voters can use their limited attention to process political information more efficiently, and therefore can make better-informed decisions.Thus, voters can base their decision on which candidate made the best proposal to solve the problem that is most important to them.
In the next section we discuss some of the main threats resulting from microtargeting.Again we roughly distinguish threats for citizens, political parties, and public opinion.

Online Political Microtargeting: Promises and Threats for Democracy
Utrecht Law Review | Volume 14 | Issue 1, 2018

Threats 4.1 Citizens
Three threats for citizens are: their privacy could be invaded, and they could be manipulated or ignored.First, microtargeting threatens privacy.Online political microtargeting involves gathering and combining personal data about people on a massive scale to infer sensitivities and political preferences.This data gathering threatens privacy.For instance, collecting personal information can lead to chilling effects.People who suspect that their behaviour is monitored may adapt their behaviour, trying to escape attention.If people know or suspect that their website visits are tracked, they may feel uncomfortable visiting certain websites. 32After all, by tracking people's internet use, a company can build a database of individuals and their interests.If people expect that an extreme right-wing party will win the elections, they might hesitate to visit websites about Islam. 33 second privacy threat concerns data breaches.Data breaches, where hackers or others access databases with personal data, are constantly in the news.To illustrate: in 2017 a marketing company contracted by the U.S. Republican Party suffered a data breach, exposing personal data of almost 200 million US citizens.'Apart from personal details, the data also contained citizens' suspected religious affiliations, ethnicities and political biases, such as where they stood on controversial topics like gun control, the right to abortion and stem cell research.' 34A third privacy threat is that personal data can be used for unexpected, and sometimes harmful, new purposes.Survey evidence from the US suggests that most people do not like online political microtargeting. 35part from privacy threats, there is a threat of manipulation.Politicians could use microtargeting to manipulate voters.For instance, a party could target particular voters with tailored information that maximises, or minimises, voter engagement.A party could use social media to expose xenophobic voters to information about the high crime rates amongst immigrants.Gorton warns that microtargeting 'turns citizens into objects of manipulation and undermines the public sphere by thwarting public deliberation, aggravating political polarization, and facilitating the spread of misinformation'. 36The targeted information does not even need to be true to maximise its impact.
Political parties could also use microtargeting to suppress voter turnout for their opponents.For example, in 2016, the Donald Trump campaign reportedly targeted African-American voters with advertisements reminding voters of Hillary Clinton's earlier remarks of calling African-American males 'super predators' to suppress African-American votes. 37Such 'dark posts' can remain hidden for people who are not targeted. 38fter all, only the targeted people see the messages.
A political party could also misleadingly present itself as a one-issue party to each individual.A party may highlight a different issue for each voter, so each voter sees a different one-issue party.In this way, microtargeting could lead to a biased perception regarding the priorities of that party.Moreover, online political microtargeting could lead to a lack of transparency about the party's promises.Voters may not even know a party's views on many topics.Balazs Bodo, Claes de Vreese Utrecht Law Review | Volume 14 | Issue 1, 2018 By way of illustration, say a politician has a profile of Alice. 39The politician has information that suggests that Alice dislikes immigrants.The politician shows Alice personalised ads.Those ads say that the politician plans to curtail immigration.The politician has a profile of Bob that suggests that Bob has more progressive views.The ad targeted at Bob says the politician will fight the discrimination of immigrants in the job market.The ad does not mention the plan to limit immigration.Ads targeted at jobless people say that the politician will increase the amount of money people on welfare receive every month.To people whose profile suggests that they mainly care about paying less tax, the politician targets ads that say the politician will limit the maximum welfare period to one year.Hence, without technically lying, the politician could say something different to each individual. 40In sum, microtargeting could be used to manipulate voters.
A third threat for citizens is that political parties could use microtargeting to ignore certain voter groups. 41A political campaign might not advertise to certain people, for instance because a party does not expect them to vote, or because it expects to win anyway in a certain area.Hence, certain groups might not be informed much about an election.A political campaign could ignore citizens who are not interested in politics, are unnecessary to win a particular local constituency, or are not likely to be mobilised for a particular party.As a consequence, these citizens are not exposed to the campaign.Therefore, certain groups may be underrepresented in a democracy.
In sum, online political microtargeting brings threats for citizens: they could have their privacy invaded, be manipulated, or excluded.Even if microtargeting were not effective, the mere collection of data would still be a privacy threat.

Political parties
Two of the main threats for political parties are that microtargeting can be expensive, and that it gives more power to intermediaries.Professional online political microtargeting can be costly. 42Certain types of microtargeting require political parties to develop know-how; to build and maintain voter records; to collect and analyse business intelligence; to design and manage campaigns; to use digital communication channels to target voters; and to integrate all those elements in a system that enables a minute-by-minute adjustment of campaigns.
The need to commission external expertise, buy access to personal data sets, and pay service providers can quickly exceed the resources of small and new parties.Therefore, elections might be decided based on the financial resources of political parties.As Bennett notes, microtargeting 'may very well consolidate power in the larger, and more well-financed, parties and make it more difficult for smaller parties to be nationally competitive'. 43While there could be strategic first-mover advantage for certain political parties, their adoption could create a bandwagon effect prompting other political parties to embrace microtargeting.
Second, microtargeting could make new intermediaries more powerful.This shift in the underlying logics and infrastructures of political campaigning gave rise to a new class of intermediaries that connect political parties and the electorate. 44In recent years, a new industry has developed that provides datadriven services.Pollsters, digital strategists, social media experts, and big data consultancies measure public opinion, build and maintain voter profiles with voters' interests and anxieties, to design and test the efficiency of personalised political messages, and deliver such messages to the screens of individual voters.
The entry of new intermediaries challenges the status quo in several ways.For instance, new gatekeeper positions and bottlenecks may arise.Some intermediaries, such as social media platforms, are in a near-monopoly position in providing certain services.This gives them unprecedented power to set prices, and dictate the terms upon political parties.

Online Political Microtargeting: Promises and Threats for Democracy
Intermediaries could also provide services to political parties at their own rate and discretion, and could even refuse to deal with political parties.Such behaviour would create new types of imbalances.To illustrate: the digital strategy firm Blue State Digital says that it will never work for a certain Dutch political party. 45eanwhile, old intermediaries, such as the printed press, struggle to adjust.Shrinking (political) advertising revenues drive cost cuts that can affect some of the core roles these intermediaries previously played in the political discourse, such as fact checking, in-depth reporting, etc.In sum, threats for political parties include the costs of using microtargeting professionally, and the growing power of new intermediaries.

Public opinion
Online political microtargeting brings several threats for the public sphere.While microtargeting could make the communication process more effective and efficient, one piece of crucial information is not being communicated: how important an issue is to the political parties themselves.
If voters receive a lot of information about one particular issue through microtargeting, they might falsely assume that the issue is one of the central issues in a political campaign.Hence, microtargeting might lead to a biased view on the issue priorities of political parties.Such a biased view is problematic, because after the elections, politicians often form coalitions and must compromise on certain policies.Microtargeting might lead to a situation in which a voter voted for a particular candidate because of his or her stance on health care, yet once in government the health-care system moves in the opposite direction, because the issue might be less central to this party than to the coalition partner.Hence, microtargeting may influence the mandate of elected politicians.As Hillygus & Shields note: 'How does a winning candidate interpret the policy directive of the electorate if different individuals intended their vote to send different policy messages?Can politicians claim a policy mandate if citizens are voting on the basis of different policy promises?' 46 A second threat for the public sphere is the fragmentation of the marketplace of ideas.A masscommunicated political campaign is organised around a small number of issues -for example health care, terrorism, and the economy.The majority of the electorate is aware of the stances of political parties with regard to these issues.An informed public allows political parties to engage in public debates, which can lead to deliberative processes.Voters can also become part of the deliberative process by engaging in the debates.However, if citizens lose interest in these overarching issues and focus on the issues that are more relevant to them, these public debates become less democratic and deliberative processes are cut short.
In conclusion, online political microtargeting brings serious threats for citizens, political parties, and public opinion.But the most serious dangers do not have to materialise, as discussed in the next section.

Nuancing the threats
In the European context, the threats of online political microtargeting should not be exaggerated, for several reasons.First, the stricter data privacy rules in Europe (compared to the US) will probably slow down microtargeting.Second, in countries with multi-party systems, microtargeting may make less sense than in the two-party US system.And there are big differences in budgets between European campaigns and their US counterparts.Third, the influence of political marketing on voters' opinions has limits.Even if people were exposed to manipulative microtargeting, people would still learn about more general political news from other sources.We discuss each point below.

Legal system
In Europe, online political microtargeting might not happen on a scale like in the US, because of Europe's stricter data privacy rules. 47Bennett suggests that the fact that microtargeting happens so much in the US can 45  be partly explained by the absence of a general data protection law in the US. 48For instance, data brokerage is a large industry in the US.Data brokers are 'companies that collect consumers' personal information and resell or share that information with others.' 49 In Europe, it is harder to lawfully obtain personal data from data brokers.
Data protection law is a legal tool that aims to ensure that personal data processing only happens fairly and transparently.Data protection law imposes obligations on organisations that process personal data (data controllers), and grants rights to people whose data are being processed (data subjects).For instance, people have the right to receive information about which personal data an organisation holds about them. 50ndependent data protection authorities oversee compliance with the rules. 51hile data protection law in Europe is generally strict, the rules for personal data about political opinions are stricter.In principle, European data protection law prohibits using personal data about political opinions, because data about people's political opinions are included in a list of 'special categories of data'. 52There are exceptions to the prohibition.For instance, such special data may be processed when the individual concerned gives his or her explicit consent.And data protection law allows political parties, under certain conditions, to process personal data about political opinions without the individual's consent. 53It seems plausible that data protection law in Europe makes gathering voter data more difficult than in the US.And data subjects could use their rights to obtain information about microtargeting.For example, a US academic uses his right to access his personal data to obtain information from the UK-based company Cambridge Analytica. 54oreover, EU data privacy law requires transparency about personal data processing, and about most forms of online targeted marketing.Every organisation that uses personal data must offer transparency about its personal data use. 55The organisation must disclose, for instance, the purpose of personal data processing. 56Hence, political parties and intermediaries that collect and use personal data for online microtargeting must disclose, for instance in a privacy statement on a website, which data they use and for which purposes.
Apart from that, the EU e-Privacy Directive requires transparency and consent for the use of tracking cookies and similar files. 57Hence, if a company uses cookies to present targeted political marketing to people, the company must inform people about the purpose of the cookie, in this case: tracking people around the internet and showing them targeted political marketing.Such transparency requirements could help to make microtargeting less opaque.
We do not claim that European data privacy law solves all privacy or election problems, or that it actually ensures that personal data are only used fairly.Compliance with, and enforcement of, data protection Online Political Microtargeting: Promises and Threats for Democracy Utrecht Law Review | Volume 14 | Issue 1, 2018 law are often lacking.Moreover, the law's transparency and consent requirements largely fail to inform people. 58Additionally, the data protection rules for political parties that gather and process personal data are somewhat vague, and different member states interpret them differently. 59Nevertheless, it seems plausible that data protection law in Europe makes microtargeting more difficult than in the US.

Electoral and political systems
There is a second reason to think that online political microtargeting will not become as big in Europe as in the US: the different electoral systems.Continental Europe's electoral systems differ from those in the UK and US.The majoritarian electoral systems in the US and the UK are characterised by a 'winner takes all' principle that makes some votes more valuable than others.In the UK majoritarian electoral system, voters directly vote for candidates in their districts.The candidate that receives the majority of votes wins the district.The elected representatives then represent their political view in parliament.In the US, every state has a number of electors.And in every state (except Nebraska and Maine), the candidate with the most votes wins all the electors. 60Due to this system, a candidate might win the majority of the votes, but not the elections.
A majoritarian electoral system, like in the US, can lead to a situation in which specific states can decide the entire election.The outcome in many states often appears to be settled before the elections, due to the demographic set-up and preferences of the majority of the population.Other states have the potential to 'swing' from one side to the other.Political parties may only invest in convincing voters in such swing states, because those votes are most important.In most European countries, which use proportional electoral systems, the weight of the votes is spread more equally. 61In such systems, parties have more reason to spread their funding evenly across the electorate.
In addition, political campaigns in Europe have much lower budgets than those in the US.In the US, the Hillary Clinton campaign raised over $623 million for the 2016 elections.Donald Trump's campaign raised over $334 million.Both campaigns also had funding from their parties and their 'super PACs' (political action committees), totalling their budgets respectively at $1.4 billion and $957 million. 62By contrast, political parties in Europe typically have lower budgets.To illustrate, none of the largest political parties in Germany has a budget of more than €47 million. 63German parties are relatively well funded in comparison with smaller European countries (the campaign budget of the largest Dutch party is less than €4 million). 64In sum, smaller budgets probably form a barrier to invest in microtargeting.

Voters do not live in digital bubbles
A third reason not to overstate the threats of online political microtargeting is that people do not live in digital bubbles.Even if people were exposed to manipulative microtargeting, they would still learn about more general political news from other sources.Voters use not only advertising to learn about politics and the election campaign, but also many other sources.A recent study found that 91% of the US population had heard about the elections in a previous week.Only 1% of that group hear about the elections through Balazs Bodo, Claes de Vreese Utrecht Law Review | Volume 14 | Issue 1, 2018 a candidate app, email, or campaign website. 65Cable TV news is still the most important information source on the political campaign in the US. 66Hence, the electorate may still have sufficient access to non-targeted information sources that can mitigate the 'filter bubble'-related effects of online political microtargeting. 67eople also learn about a politician's views from watching TV news and from conversations with friends or colleagues.These other sources may still sufficiently inform voters about the campaign in general: the issues central to the campaign, and the priority candidates give to specific problems.More generally, it cannot be ruled out that companies that offer microtargeting services to politicians exaggerate how effective microtargeting is.In conclusion, online political microtargeting brings serious threats.On the other hand, the threats should not be exaggerated.Table 1 provides an overview of the promises and threats of microtargeting.

Regulating online political microtargeting
In this section, we will highlight the possibilities for national legislators which want to regulate online political microtargeting.But first we will discuss the right to freedom of expression of political parties, which may limit the possibilities for regulating microtargeting.

Freedom of expression and regulating online microtargeting
Any law that restricts political communication must comply with Article 10 of the European Convention on Human Rights, which guarantees the right to freedom of expression.While the right to freedom of expression is not absolute, governments may only restrict this right in very limited circumstances. 68The European Court of Human Rights in Strasbourg, which is tasked with interpreting the Convention, ultimately decides whether government restrictions on the freedom of expression are compatible with its guarantees.Is online political microtargeting protected by Article 10?
The Strasbourg Court has held that 'publishing information with a view to influencing' voters is an exercise of freedom of expression. 69On the basis of this principle, online political microtargeting would seem to come within the definition of freedom of expression.Indeed, a closely related means of political communication, paid political advertising on television, has also been held to be covered by Article 10. 70 Similarly, distributing election leaflets, 71 and displaying political posters, 72 are covered by the right to freedom of expression under Hendrickx, 'supra note 19.46 D. Hillygus & T. Shields, The Persuadable Voter: Wedge Issues in Presidential Campaigns (2008) p. 14. 47 See in more detail about the interplay between European data protection law and political microtargeting: Bennett, supra note 7. Balazs Bodo, Claes de Vreese Utrecht Law Review | Volume 14 | Issue 1, 2018

Table 1
Promises and threats of microtargeting for citizens, parties and public opinion