Looking back over the campaign, everyone now seems to see that there were a few key moments when John McCain did things that surrendered whatever chance he had to beat Barack Obama. At the top of the list has to be the choice of Sarah Palin as his vice-presidential nominee -- a choice that seemed fatal from the first for those who had eyes to see it, and soon revealed itself as such over the concluding weeks of the campaign. And McCain staffer and alter-ego Mark Salter is now conceding that the campaign suspension is probably another.

But what is easy to miss in these key moments is that most of them weren't simply what McCain did but how Obama reacted -- and the critical synergy between the two.

The campaign suspension was the key example.

It wasn't just that McCain suspended his campaign (and tried to postpone the debate). That wasn't the point at all. He unilaterally suspended his campaign and dared Obama not to suspend his. That was the key. Either Obama had to follow McCain's lead and suspend his campaign or reveal himself as the self-serving, all-about-himself, unpatriotic freak McCain's campaign had spent so many millions of dollars to portray him as. It was a classic play at the Republicans' 'bitch-slap' theory of electoral politics, with all the gendered weight and macho-hierarchy-setting the unlovely phrase implies.

But Obama didn't budge. I think there were a lot of Democrats who were really worried that McCain had put Obama in some kind of box or that Obama would see it as such and react accordingly. But he didn't.

And it went from McCain bigfooting Obama (with all that would have entailed), to Obama turning the stunt around on McCain. It undermined one of McCain's key selling points against Obama -- that he was tougher, more seasoned under pressure -- and further cemented the image of a man who was erratic and showed questionable judgments under pressure.