It reminds me a lot of John Kerry's late revelation in 2004 that Iraq was "the wrong war in the wrong place at the wrong time." Kerry could have had the courage of his convictions if he'd opposed it from the beginning, or somehow made a strong pivot in really opposing it in all its tragic awfulness. But he never could make the case, because he'd been hedging all along.
I think that if McCain had taken a principled stand against the bailout, he could have gained (some) traction in the polls as a "free-market populist," or whatever the House Republicans are now calling themselves. But he didn't. In fact, as we all know, his handling of that situation has provoked nothing but embarrassment and scorn even among his party mates.
But it didn't have to be that way.