AP Photo

Whatever happened to conservative pragmatism? Ideology used to belong to parties of the left. The right concerned itself with the exercise of power. On either side of the Atlantic, politics has been turned on its head. The conservatives are now the utopian zealots forsaking centrist broad appeal for ideological absolutism. Liberals and social democrats are the new realists. Last week more than half the Republicans in the House of Representatives voted against a deal to prevent the US going over the fiscal cliff. This was in defiance of their own congressional leadership, of the fact that Barack Obama won the election and of the overwhelming weight of public opinion. For the rebels the important thing was to keep their no-new-taxes pledge. Never mind the views of John Boehner, the...