So far, however, public opinion seems to be unmoved. In a Gallup poll released this morning, 44 percent of respondents said they preferred President Obama’s budget plan, versus 43 percent who said they preferred Mr. Ryan’s Republican approach.

If these numbers hold, this is good news for the Republicans. Mr. Ryan’s budget — while not exactly popular on its own terms — will have accomplished some other objectives for the party, such as placating Tea Party supporters and shifting the ideological goalposts on the welfare state.

But Republicans ought to be careful about declaring “Mission Accomplished”.

What polls like Gallup’s seem to reflect is the overall partisan split in the country. In the poll, 44 percent said they preferred Mr. Obama’s budget approach. That is identical to Mr. Obama’s average approval rating — also 44 percent — in Gallup’s polling over the past three weeks.