Helena Bachmann

Special for USA TODAY

GENEVA — Political parties campaigning to stem the rising tide of immigrants pouring into Europe are resorting to posters that have racial undertones and denigrate Muslims.

The latest example: a poster of a white sheep kicking a black sheep off the Swiss flag promoted by Switzerland’s largest party in a failed bid to win last month's referendum that would have expelled immigrants convicted of crimes.

The Swiss People's Party's anti-immigration message — "Make the country safe, say yes to deportation of foreign criminals” — did not persuade a majority of Swiss to support its view. The Feb. 28 referendum was defeated by 59% of voters.

While the black sheep may appear to be a racial metaphor, “it’s not about race,” said Georg Lutz, director of the Swiss Electoral Studies at the University of Lausanne. “It symbolizes a foreigner, an outsider.”

Portraying foreigners as black sheep is not a new tactic for the party. It used a similar image for its successful 2007 parliamentary elections. That poster showed three white sheep booting a lone black one out of its flock.

In a 2011 campaign, the Swiss People's Party was found guilty of racial profiling after an immigrant from Kosovo slashed the throat of a party member after a quarrel. The party promoted a poster showing black shadows marching across a Swiss flag with the caption, “Kosovars slash Swiss. Stop mass immigration.”

Two Kosovo nationals filed a complaint and the court ruled that the poster incited hostility against an ethnic group. Party members responsible for the advertisement received a fine and a suspended sentence.

Other anti-immigration campaigns in Europe have used similar negative images of foreigners.

In 2014, Germany’s far-right National Democratic Party re-launched a controversial poster that showed three Middle Eastern people sitting on a flying carpet with a caption: "Have a safe flight home."

That same year in Austria, the country’s Freedom Party circulated a poster showing a blond woman with the phrase: "Too beautiful for a veil."

And back in 2008, Italy’s Northern League distributed an election poster showing an American Indian with the slogan: "They suffered immigration; now they live on a reserve.”

The anti-immigration campaigns come as Europe copes with a huge influx of migrants fleeing war and poverty in the Middle East, Asia and Africa.

In Switzerland, foreign-born residents make up nearly a quarter of the population, compared with 13% in the United States.

But Switzerland has a long tradition of opening its borders to immigrants and refugees, and the posters have sparked criticism at home and abroad. The Geneva-based Human Rights Council said the images “incite hatred” and called for the removal of offensive posters from public spaces. The Swiss People's Party refused, citing free speech.

That right has kept the party out of legal trouble. In the past several years, private citizens filed two lawsuits against the party. One was over the sheep poster and the other over the image showing a veiled woman and warning that, with the influx of Muslims into the country, Switzerland could become like Iraq. In both cases, judges ruled that the posters could not be banned.

"In a democracy, it is important that opinions can be presented even if they offend a lot of people," the court added.

The Swiss People's Party argues that a disproportionate number of foreigners are lawbreakers. Government statistics indicate they make up over 70% of the prison population. In all of the party's campaigns, migrants are portrayed as dishonest and dangerous individuals who abuse the country’s welfare system and perpetrate crime.

The party regularly uses Switzerland’s referendum-based direct democracy — in which any individual or group can get an initiative on a ballot by collecting 100,000 signatures on a petition — to launch controversial measures and equally contentious campaign materials. If passed, the proposals become law.

In 2008, the party launched a proposal to make the process of naturalization more difficult with a poster depicting dark hands grabbing Swiss passports. However, over 63% of voters rejected the measure.

The next year, the party pushed through a referendum, approved by 57% of voters, to ban the construction of minarets on the country’s mosques. The campaign sign showed a woman dressed in a burqa, standing on a Swiss flag in front of minarets shaped like missiles.

Some of Europe’s other populist groups have copied the Swiss posters. The minaret artwork found its way to France’s National Front Party for the 2010 regional elections. Germany’s National Democrats and the Czech Republic’s National Coalition recycled the sheep image.

“The goal of these posters is to create controversy, provoke and grab attention. In that sense, they’ve been very successful,” Lutz said.