Street protests are omnipresent. Almost on a daily basis, people take the streets to voice their grievances about some state of affairs, such as budget cuts on higher education, police violence, or gay rights. The prevalence of this form of political participation is, however, not matched by research on the matter. That is to say: comparative research, which allows for a systematic analysis of protest demonstrations, is rare.

The PhD-thesis Protest! Studies on Protest Politicization, Perceived Protest Atmosphere and Protest Policing aims to address this deficiency by presenting a systematic analysis of street demonstrations and their core actors (demonstrators and the police). More specifically, the thesis comprises studies on how demonstrations differ in their level of politicization, how demonstrators perceive protest atmosphere and why, and how the police manage European protest events.

These studies are based on various datasets. Firstly, a dataset of nearly eighty European street protests was exploited. This dataset had been gathered by the international research project Caught in the act of protest: Contextualizing Contestation (CCC). In addition, several Dutch protests were analyzed, using the CCC project’s methodology. In a nutshell, this methodology entailed that protests were systematically studied before, during, and after they were taking place. Furthermore, data were gathered from different vantage points. So, before the events, protest organizers and police officers were interviewed. During the events, protesters were asked to accept a questionnaire, and researchers made observations. After the events, questionnaires were collected and researchers reported their observations. Also, protest organizers and police officers were interviewed again, and researchers conducted media analyses.

The analyses of these rich, mixed-methods datasets provided the following insights:

• To determine how political a protest is, researchers need to focus on six different protest features: the extent to which protesters are angry and fight for a collective good (1-2), an opponent is identified and vilified (3-4), and a claim is specific and combatively made (5-6). So, at a more political protest, demonstrators are angrier, and participate more out of collective motives (than individual ones). Also, at a more politicized event, the opponent (e.g., Prime Minister) is more clearly identified and more severely vilified, and the claim (e.g., to abandon foreseen austerity measures) is more specific and more combatively made.

• Protest atmosphere ranges from very unpleasant to very pleasant, at least, from a demonstrator’s perspective. The more demonstrators consider the atmosphere pleasant, the more they identify with other demonstrators, and feel empowered. Interestingly, a demonstrator’s atmosphere perception also influences his or her willingness to participate in future collective action.

• When it comes to intergroup conflict, demonstrators perceive four different atmospheres: harmonious, volatile, tense, and chaotic. These atmosphere perceptions are shaped by individual characteristics and demonstration characteristics. For example, demonstrators who are male, and those who participate in an event that is repressed by the police, are more likely to perceive a conflictual (i.e. volatile, tense, or chaotic) atmosphere than a harmonious one.

• The police forces manage threatening national European protests quite differently than (typically threatening) transnational protests. That is to say: ‘strategic incapacitation’, a relatively repressive policing style that was introduced around the turn of the twenty-first century to manage transnational protests, has hardly diffused to national European protests.

These findings are relevant for protest researchers, but will also be of use to protest organizers, protesters and the police. Protest organizers can motivate protesters to participate in future collective action by staging a protest event that is pleasant, but also has a clear political aim. People who (intend to) participate in a national European protest do not need to worry that the police will engage in strategic incapacitation. Lastly, by knowing how and why protesters experience protest atmosphere (in terms of intergroup conflict), the police will be better able to predict which events will get out of hand.