The right-wing nationalist Swiss People's Party (SVP), which featured a picture of a dark-skinned man ripping up a Swiss flag in its election posters, leaped from fourth to first place in the popular vote in yesterday's general election, according to initial results.
Under Switzerland's mix of direct and proportional representation, the projected outcome would make the People's Party the third-largest group in the lower house, just behind the Social Democrats and the liberal Radical Democrats.
The shock result is likely to put pressure on the so-called magic formula coalition of all four main parties which has governed Switzerland for the last 40 years.
Mr Christoph Blocher, the most high-profile member of the party, said it would no longer be satisfied with the one seat it has in the cabinet to the two held by the other three parties. "If we are stronger than one of the other three governing parties, then it would seem only natural that we get a second seat," he said.
He left open the possibility that the SVP could leave the government if it did not get its way on toughening asylum laws and cutting taxes. "If we have to go entirely into opposition, then we would go entirely into opposition," he said.
Initial predictions based on early results last night indicated that the SVP got 23 per cent nationally, ahead of the 21 per cent of the previous leading party, the Social Democrats.
The Social Democrats were shocked by losses in many cantons, even coming third in some areas. "I did not think that we would lose votes," said the Social Democrats' president, Ms Ursula Koch, blaming the poor showing on the party's supporters not turning out to vote.
But the SVP seemed to have connected with Swiss worries about immigration and increased involvement in international organisations. It campaigned on a clear platform against closer ties with the European Union, to curb immigration and cut taxes.
Accusations against Mr Blocher of Nazi sympathies seem to have failed to deter voters. He has been accused of showing sympathy with a man jailed for denying the Holocaust ever took place and has been repeatedly compared to Austria's Mr Jorg Haider, whose far-right party took second place in that country's general election earlier this month.
Both men are charismatic millionaires with political platforms firmly based on isolationist, anti-immigration policies.
Mr Haider has survived calling former SS members "decent men with character", while Mr Blocher has been quoted as saying "How right he is," in response to a book written by a man since jailed for denying the Holocaust.
Mr Blocher insists his comment related only to the book's title, The Decline of Swiss Freedom, and not to its content. "I reject any form of revisionism as absurd," he said. "The same goes for any form of anti-Semitism, right-wing extremism and racism, and that's well known."