The paper analyzes the effect of different kinds of party Euroskeptic messages on citizens’ support for the integration process. The European Union is a political system that people can perceive as distant, compared with the national one, because of its complex functioning and of the less direct influence that citizens have on it; therefore, it is likely that people lack the relevant information for autonomously constructing their own idea of the integration process and, because of this, they rely on their preferred party’s positions as heuristic.

But are some party positions more persuasive then others? According with a growing body of literature, negative messages will hold more weight than those in favor because, when making a decision, people place more emphasis on avoiding potential losses than on obtaining potential gain. In the studies on the support for the European Union, this tendency implies higher persuasion power of those parties that oppose new steps toward a closer integration, and therefore an advantage of Euroskeptic parties on pro-Europe ones. These results, however, are based on the assumption that a pro-European party cannot express a negative message. This paper points for the first time to the fact that when defending the integration process from steps back, pro-European parties are actually providing negative messages about policy proposal from Euroskeptic parties. The paper uses experimental data for testing whether or not the persuasive advantage of negative messages holds also in this last case.