More or less vulnerable? Variation in the extent to which mainstream political parties’ Voters consider voting for radical right populist parties

West European party systems have undergone profound changes, one of the
most obvious being a marked decrease in vote share going to the mainstream
parties whose domination of electoral politics used to be taken for granted,
along with an increase in votes going to more radical, populist contenders—
most (but not all) of them on the anti-immigrant right. These two changes are
widely assumed to be linked. Yet the potential impact of the populist radical
right on the electoral performance of (western) Europe’s other party families
may well be uneven. We use European Election Study survey data to explore
which parties (and party families) might be most vulnerable to seeing their
voters defect to the populist radical right. We find that, although it has become
commonplace to observe that it is the social democratic centre-left which is
most vulnerable in this respect, it is actually centre-right parties which, at this
point anyway, would seem to have most to lose. But they are not alone:
interestingly, the voters of radical left parties are also vulnerable to the appeal
of the radical right.