Screw the polls. Republicans will be on the right side of the spending debate. They’ll be on the right side of the substance debate, too. Instead of bickering about Romney’s tax returns and repeating the obvious but unhelpful observation that the unemployment rate sucks, we’ll actually have to debate serious problems and solutions. That’s great for the country.

I’m not saying Ryan is the nation’s savior. He has serious flaws. His discipline on spending isn’t matched by restraint on tax cuts. He was wrong to oppose the Simpson-Bowles plan. Democrats will hammer him on the tax side, and he’ll deserve it. But that, too, will make the debate productive: Each side’s dogmas will be exposed, with fiscal responsibility as the governing standard. And unlike many of his colleagues, Ryan isn’t a wanker or a hater. He’s in it for solutions, not spite. He’ll be the best kind of debater, open to criticism and amenable to compromise.

It speaks enormously well for Romney that he made this choice. It tells me he’d run the country the same way he ran Massachusetts: as a prudent, numbers-oriented businessman.