With the war (which McCain supports) unpopular, and the economy and broader outlook deeply negative, some analysts have been tempted to cast the general election as a slam-dunk for the Democrats. That's not the case; depending on the poll, Obama leads McCain narrowly or not at all, and the two divide public preferences on issues and attributes alike.
There are two fundamental reasons. One is that this is more a center-right than a center-left country. On average this year 34 percent of Americans have described themselves as conservatives, vs. 23 liberals. (What closes the gap is that moderates are more closely aligned with the Democratic Party.) The other is a generation-long trend in political party affiliation, which, despite ups and downs, has been in the Republicans' favor. On average in 1981, when ABC News started polling, Americans were 13 points more apt to call themselves Democrats than Republicans. So far this year, it's been 9 points. The Republicans did even better --- absolute parity with the Democrats --- in 2003, before public views of the war and then the economy went sour, prompting an exodus from the president and his party.
That leaves us with the last wildcard of 2008, George W. Bush. If the Democrats make the election a referendum on his presidency, they gain a vast advantage. If, instead, it's a post-Bush election, all bets are off.