One by one, Europe’s traditional centrist parties face a difficult choice: when will they swallow their scruples about post-1945 fascism and agree to cooperate with their resident far-right ethno-nationalist parties?

Next stop: Sweden. Next week’s election looks set to position the once-probable extreme Sweden Democrats, now with more than 20% of the vote, as the major party on the right – forcing their more centrist right-wing counterparts to get on board, as no Sweden Democrats means no right-wing government.

It’s a dilemma. Do they choose democratic solidarity at the price of a continued social democratic government? Or for a “no enemies on the right” agreement that legitimizes the post-fascist party that was once so fringe that it only broke into parliament in 2010?