Two and half years ago, when the situation in Iraq was pretty much at its worst Bush's popularity was already headed steeply down (though not yet as low as it is now), I was talking to one of my very liberal friends, and he commented: "You Republicans enjoy it now. We'll take back congress at the next election, and there is no Republican on earth who could win the presidency after eight years of Bush. He's destroyed your party for a generation."
"What if we nominate McCain?" I asked.
He considered. "There's no way. McCain is the one Republican I would consider voting for -- and that means you people would never elect him. Maybe he'll switch parties when we take over."
Well, here we are. And now my liberal friends assure me that "this is not the McCain we knew." He's "McSame". He's "Bush's third term". He's "McFossil". He's a "batshit insane" warmonger who wants to start World War III. And yet four years ago, when he called out Michael Moore in a speach at the Republican convention, Moore claimed he was hurt and said the he liked McCain and admired him. Senator John Kerry reportedly wanted McCain as a running mate.
What happened here? So far as I can tell, McCain is still very much whatever he always was. I'm not myself a fan, but he does have an Old Roman sort of virtue that I admire to an extent. He is not a principled conservative, or indeed an adhereant to any intellectually defined political or economic philosophy. But he is clearly a firm believer in honesty, honor, and service to the Civitas. He's devoted his life to the Res Publica, and I think he would probably do less damage to the country and the world than Obama -- though I suspect that if he is elected it will be longer before a real conservative is able to win back the presidency than if we have a Democrat in the White House. (However since we vote for the good of the country rather than the party -- I will probably vote for him.)
However, McCain has lost all his support from across the aisle because electoral politics is not just a matter of competing political philosophies -- it is also a matter of tribalism. While there are very real and important differences of political, moral and economic philosophy between the two major parties in America, the tribalism of party membership at times seems to have equal or greater force in fueling debate.
Tribalism can cut both ways. Although he sustained a good bit of criticism from conservatives, President Bush did not have the fight from congressional Republicans over No Child Left Behind, the Medicare Prescription Drug Benefit or the creation of the Department of Homeland Security that any Democratic president would have recieved over such massive increases in government power and beaurocracy. In that case, tribalism protected him.
Over the years, McCain has received much admiration from liberal and moderate quarters -- but in an election year (and with a new, younger media darling for the Democratic nominee) his proposals (even some very liberal ones which I do not like, such as his cap-and-trade carbon policy) are being ignored or greeted with derision. Tribalism requires that any policies put forward by the presidential nominee of one party be scorned by members of the other party -- even if they themselves advocated similar proposals in the past.
The tribal lense also affects how people view the world. For instance, expect many Democrats to be much less worried about government wiretaps and the continued presence of US troops in Iraq if Obama is president rather than McCain. Similarly, expect a number of Republicans who have been curiously quiet on such issues to recall that they don't trust the government and don't want it doing wiretaps, and that they don't think that US troops should be used for open-ended nation-building exercises, if Obama wins.
And notice how it is always whichever party is out of power which is able to notice what things are going wrong (or may go wrong) with the economy -- while those in power may recognize are problem here or there, but are sure it is only the result of the cycle and we're doing everything we can.
None of which is to say that there aren't very real points which are made, and sincerely meant, by the most partisan. (And certainly, I can be one of the more partisan at times.) But especially for the six months leading up to the presidental election every four years, one can expect much of the political discourse to be more about tribe than about principles.