French President Emmanuel Macron speaks during the Intelligence College in Europe meeting at the Foreign Affairs Ministry in Paris on March 5. Macron urged voters in 28 nations to choose a stronger European Union. (Ludovic Marin/Pool/AP)

Earlier this month, French President Emmanuel Macron called for a “European Renaissance,” declaring that the European Parliament elections scheduled for May “will be decisive for the future of our continent.”

Macron distributed his open letter to European voters via social media, declaring: “Never, since the Second World War, has Europe been as essential.” He suggested that it was time for Europe to jointly adopt a minimum wage, prohibit political party contributions by foreign powers and create a common asylum policy, among other things.

With so much at stake, does reminding voters about the devastation of war increase support for European cooperation?

Macron’s hope is that these changes revive public enthusiasm for the European integration project — a five-decade effort to create a unified and peaceful Europe. This goal is under assault from Euroskeptic and populist forces.

Europe’s politicians often bring up World War II

Although directly addressing European voters via Twitter to release an open letter is unusual, it is not uncommon for European politicians to reference the devastation of World War II to convey the added value of European cooperation today. In 2004, former German chancellor Helmut Kohl said: “The most important rule of the new Europe is: There must never again be violence in Europe.”

In 2013, Luxembourg’s Prime Minister Jean-Claude Junker — now president of the European Commission — stated that “anyone who believes that the eternal question of war and peace in Europe is no longer there, risks being deeply mistaken.”

Europe’s political figures like to remind their constituents of the devastation of World War II to spell out the added value of the European Union and increase support for European cooperation today. But does this kind of rhetoric work? We ran an experiment to find out.

Our findings suggest that reminding people of the wartime devastation increases support for European cooperation — but only when it comes to financial assistance for member states in need, not in the areas of intra-E. U. migration or European defense.

How did we do our research?

To find out if recalling the devastation of World War II actually influences public opinion, we embedded a survey experiment in a wave of regular European opinion poll Eupinions in July 2017 for six E.U. countries — France, Germany, Britain, Italy, Poland and Spain. We designed the experiment to activate people’s memory of the wartime devastation through a vignette that resembles this type of political rhetoric. Here’s how we worded the experiment’s vignette:

The Second World War was a global war that lasted from 1939 to 1945. It was one of the deadliest military conflicts in human history. Over 60 million people were killed including innocent children. The war had devastating effects on the European continent. Many people lost everything, their economic livelihoods, their homes or even loved ones.

We randomized the order in which respondents received this vignette. One group of respondents, the treatment group, read the vignette before answering a set of questions eliciting their views about cooperation in Europe. A control group, in contrast, received the vignette after answering these questions. The questions asked people about their support for European cooperation (on a 10-point scale) in three areas that have been highly contested recently:

1. Financial assistance: To what extent do you think that your country should provide financial aid to another E.U. Member State facing severe economic problems?

2. Rights of E.U. migrants: To what extent do you think that your country should try to limit the rights of E.U. citizens to work and live here?

3. European army: To what extent do you think your country should help to establish a European army?

What do our findings suggest for Macron’s “European Renaissance?”

Yes, we found that reminding people about the sheer devastation of World War II increases their support for providing financial assistance to a struggling member state. Compared to the control group, those exposed to the wartime devastation vignette support financial assistance by about 2.5 percent more. That said, this rhetoric has little to no effect on support for extending the rights of E.U. migrants, or aiding the establishment of a European army.

Our results suggest that the effects are very similar across four of the six E.U. countries — except for Italy and Poland. Reminding Italian and Polish respondents about the history of World War II had no discernible effect on any of the three measures of support for European cooperation.

One way to read these findings is that they point toward a transactional nature of European public opinion. This suggests Europeans may be willing to pay for more cooperation on the European continent, but less willing to cooperate further when this would involve a larger infringement on their national community — such as granting further rights to other Europeans living in their country or sending fellow countrymen into battle.

We think these findings are important for Macron’s dream of a “European Renaissance” because they suggest that his appeal based on European history might be somewhat helpful. His message may garner some support, but seems unlikely to convince Europeans to engage more with the dream of a unified Europe.

Catherine E. De Vries (@CatherineDVries) is a Westdijk chair and professor of political behavior in Europe in the department of political science and public administration at the Vrije University Amsterdam and the author of the book “Euroscepticism and the Future of European Integration.”

Isabell Hoffmann (@eupinions) is the founder of Eupinions and an expert researcher on democracy and legitimacy in the E.U. for the Bertelsmann Stiftung.