At the Columbia Journalism Review, Brendan Nyhan makes a good point about the pre- and post-election CWs:
The media has undergone a strange change of mindset. Immediately before last Tuesday’s election, many reporters and commentators ignored or dismissed the consensus among forecasters and betting markets that President Obama was very likely to defeat Mitt Romney and acted instead as if the candidates were neck and neck or Romney was ahead. Afterward, however, coverage of how Obama won betrayed far less uncertainty about the outcome of the election, which was frequently portrayed as a fait accompli—an inevitable consequence of how Romney’s image was defined by Obama’s early ads or overwhelmed by the President’s superior ground game.
The shift from “anything can happen” to “Romney never had a chance” was obviously in the interest of Romney campaign personalities, who would prefer to appear as having fought a hopeless, uphill battle rather than blowing a lead or losing “momentum.” But “hindsight bias,” says Nyhan, affects a lot of political journalism. What connects the pre- and post-election accounts we are reading is the persistent belief in campaign events as crucial: it’s not the “fundamentals” of external forces (e.g., the economy) or party ID that matter, but debates, ads and long-planned GOTV efforts. Many writers are simply deciding that the “game-changers” happened earlier. The official CW account of the election, of course, may ultimately depend on who writes a book that gets picked up by HBO.