As long as far-right parties – known chiefly for their vehement opposition to immigration – have competed in contemporary Western Europe, scholars and observers have been concerned about these parties’ implications for liberal democracy. Many originally believed that far- right parties would fade away due to a lack of voter support and their isolation by mainstream parties. Since 1994, however, far-right parties have been included in 17 governing coalitions across Western Europe. What explains the switch from exclusion to inclusion in Europe, and what drives mainstream-right parties’ decisions to include or exclude the far right from coalitions today?

My argument is centered on the cost of far-right exclusion, in terms of both office and policy goals for the mainstream right. I argue, first, that the major mainstream parties of Western Europe initially maintained the exclusion of the far right because it was relatively costless: They could govern and achieve policy goals without the far right. During this period of exclusion, however, major parties of both the left and right attempted to win back voters lost to the far right by enacting more restrictive immigration policies; they would borrow from the far right as long as it was beneficial.

Second, I argue that the mainstream right has increasingly treated the far right as it would any other party during coalition decisions. Major mainstream parties prioritize being in government, and will select the coalition that offers both stability and the ability to achieve policy goals in areas of greatest importance to them at the time. As the far right continued to attract voters throughout the late 1980s and early 1990s, the mainstream right realized that working with the far right – which was now a more useful partner, as it had more legislative seats – might result in more advantageous policy compromises. Once far-right parties could be useful to the mainstream right, exclusion became a more costly strategy.

Third, far-right parties can be attractive coalition partners to the mainstream right be- cause they are flexible on most issues – immigration excepted – and thus more willing to give the mainstream right its preferred policies in exchange for gains in immigration. Additionally, far-right parties are nearly always smaller than the major mainstream-right parties, so the mainstream parties are able to carry more weight in coalition decisions and obtain important ministerial positions.

I demonstrate my argument through in-depth case studies of Austria and the Netherlands, from the 1980s through the present. Both countries have had far-right parties in and out of government, providing important variation on the dependent variable. Finally, I show the wider applicability of my argument in two ways by extending my arguments about inclusion and exclusion to coalition-like agreements in the United Kingdom and France, as well as to mainstream left responses to far-left parties in Europe.