BERLIN – When the Sweden Democrats (SD) agreed to support the mainstream moderate party in September, it was the first time that a Swedish government was dependent on support from Far to the right. Days after that government was formed, an election was held in Italy Giorgia Meloni to power as the country’s first hard-right leader since Mussolini, with support from more centrist parties. The new Swedish and Italian governments are the latest examples of the mainstream right in Europe breaking the taboo by collaborating with the radical right – the so-called cordon sanitaire – following examples from Austria, Estonia and Finland.

On the issue most important to the hard right – immigration – the recently empowered extreme right is already having an impact on government policy. SD is pushing Sweden to oppose the EU’s migration policy, including reportedly trying to block Romania and Bulgaria from joining the borderless Schengen area. Meanwhile, Meloni’s government has had a row with France by refusing to let Ocean Vikinga refugee rescue boat, docks in its ports.

Far-right leaders in other European countries have celebrated the coming to power of their Italian and Swedish sister parties. Santiago Abascal, the leader of Spain’s far-right Vox, tweeted pictures of himself with Meloni after her election. “Everywhere in Europe, people are striving to take their destiny back into their own hands,” Marine Le Pen, the far-right leader who came second in this year’s French presidential election, said after the Swedish result. But do the far-right’s successes in Sweden and Italy make it more likely that sister parties in other countries will win their own elections?

There are two aspects to the question. The first is whether voters take note of political developments in other countries, such as electoral victories for far-right parties, when deciding how to cast their own votes. In practice, ordinary people tend to pay little attention to politics outside their own countries, edge cases aside, according to the political scientists I spoke to. “I think politics is much more national, or domestic if you like, than much of the international reporting suggests,” said Cas Mudde, a professor at the University of Georgia. Still, he added, “there is no doubt that the normalization of the extreme right in more and more Western countries is having some effect on countries that still use a cordon sanitaire.”

And if the newly empowered far-right is a remarkable success in countries like Italy or Sweden in implementing favored far-right policies, especially on migration, which can resonate with voters in other countries. “There is work showing that the success of far-right parties in one region increases the likelihood that the far-right will also succeed in neighboring regions,” said Vicente Valentim, a researcher at the University of Oxford.

The other side of the question is probably the more consequential. Voters may not pay much attention to politics in other countries – but elites, including politicians, do. Right-wing parties are already talking with and learning from each other. A good example of parties sharing lessons from elsewhere is the fallout from Brexit. If many European far-right parties once campaigned to leave the EU, the mounting costs of Britain’s vote to leave the bloc in 2016 have all but silenced advocates of further exit. Today, far-right parties tend to advocate reform rather than leaving the EU, a proposal that no longer appeals to voters in the same way.

Prime Minister of Hungary Viktor Orbán has also long inspired far-right parties across the EU, which see his iron grip on power and anti-migrant policies as a model for their own. Meloni “was very close to Orbán, who she repeatedly said explicitly was her model of a European leader,” said Teresa Coratella, program director at the Rome office of the European Council on Foreign Relations. However, she added that Russia’s invasion of Ukraine caused Meloni to distance himself from pro-Kremlin Orbán.

For political elites, the issue of the eroding norms against far-right parties working with parties traditionally seen as moderate is key. Whereas in the past parties from the mainstream right held on cordon sanitaireleaders are increasingly willing to disregard that norm if the Riksdag’s arithmetic requires it to gain power, as in Sweden.

If the center right in one country sees that its counterparts in others can form coalitions with the far right and suffer little or no consequences politically or internationally, it will be more willing to have the opportunity to do so itself. This means that the experiences of parties such as the Swedish Moderates are probably the most instructive of all. If the center party Austria’s People’s Party made itself a European pariah in 1999 by forming a coalition with the far-right Freedom Party, the Moderates have suffered practically no penalty for governing with the support of the Sweden Democrats.

This eroding norm is likely to influence politics across the EU. Spain could be the next test case. In April, the centre-right People’s Party (PP) formed a coalition with Vox in the northern region of Castile and León, bringing the hard right into a regional government for the first time ever. (The deal was given the green light by national PP leader Alberto Núñez Feijóo.) With the norm against collaboration with the far right broken, that arrangement could set a precedent for national politics after elections scheduled for December next year, when the PP could claim Vox votes to form government.

Nevertheless, if in some countries cordon sanitaire weakens or breaks completely, it continues to hold others. In Germany, for example, cooperation between the mainstream right and the extreme right is still taboo on a formal level. In France, too, the two candidates for the leadership of the once-dominant Republican Party have both rejected the prospect of an alliance with Le Pen’s National Rally (not least because, given the balance of power on the right, the centre-right would likely be the junior partner in such an arrangement).

As the taboo against collaboration between the mainstream and the radical right breaks down in a growing number of countries, parliamentary arithmetic will determine whether such parties remain out of power. As Mudde put it to me: “If preferred coalitions depend on far-right cooperation, mainstream parties will choose them.”

[See also: Is Volodymyr Zelensky losing the support of the West in Ukraine?]