In theory, theory is the same as practice. In practice, it's different . . .

Apropos of McCain's apparent vendetta against Amtrak, Matt says:

That's just one piece of the larger, somewhat odd, McCain puzzle on climate change. He's adopted a cap-and-trade proposal, but not really one that's far-reaching enough according to most scientists. And he doesn't flesh out his vision of a low carbon America very much -- there's nothing about increased transit ridership or any other explanation of how emissions will be reduced. Nothing, that is, except a love of nuclear power.

I'm still digging into the two proposals, but on first glance, the major differences between them are more apparent than actual. The extent of the political compromise required is going to lock such a scheme into a pretty narrow range, no matter who pushes it. Obama's probably more committed to cap-and-trade, but in the "Only Nixon can go to China" sense, McCain probably would be able to push his plan through with fewer changes.