Yglesias doesn't think the sort of spending reforms Britain is undertaking are possible in America:
[T]he system they have in the UK where you can simply sweep opposition objections aside is actually the right way to do bipartisanship. Call it bipartisanship by alternation. When Labour wins the election, Labour has the chance to implement a bold agenda creating and expanding programs in a way that they think will make Britain a better place to live. Then when the Tories come in, they’re able to be brutal in their efforts to pare back or eliminate things that they think aren’t working. Over the long term, you get a trajectory where programs survive if and only if they’re so widely regarded as successful that no mainstream party would dare abolish them.
The problem is that you can also get overkill - like the over-reach of the 1945 government, which eventually required the radicalism of the Thatcher years to return Britain to balance. But in times of fiscal crisis, Britain's elected five-year dictatorship can do what is necessary and clearly face accountability. America's system, in contrast, can lead to paralysis if partisanship and polarization are as grotesque as they now are.
But it is also true that polarization in Britain is much less right now than in America. Remember this is not just a Tory budget. It's a Tory-Liberal budget. It would be the equivalent of Reagan and Bush II winning enough Democrats for their tax cuts; or Obama winning enough Republicans for his modest stimulus. Which, of course, reveals the difference. Obama got zero GOP votes for a stimulus a third of which was tax cuts in the worst downtrun since the 1930s. The current GOP is far more rigidly ideological and economically irresponsible than any other governing party in the West right now.