Recent public opinion dynamics have favored Democrats, to be sure, leading, in conjunction with the curent economic disaster, to some predictions of a 1932-style Democratic landslide. But as Chris Bowers points out at Open Left today, we’re in an era where the margin of error, and of victory or defeat, is much smaller than in the past.
Here’s Chris’ analysis on the limits of the swing vote and its implications.

8.5% is the maximum victory: First, as I warned on Monday, please keep in mind that an 8,5% national victory is the maximum. In the last sixteen national elections (U.S. House and Presidential), the largest victory was Bill Clinton’s 8.51% victory in 1996. The simple fact is that no one wins by double digits anymore. This goes for the large Republican victories in 1988 (President–7.72%), 1994 (5.9%), and 2002 (4.6%). It also goes for the large Democratic victories of 1992 (President–5.56%), 1996 (President–8.51%) and 2006 (7.9%). “Landslides” are now 5-8% national victories, not anything larger. Given that a very real percentage of Democrats and Independents won’t vote for him because he is black, it was always absurd to think that Obama was going to break this mark. When Obama reached an 8% national lead, the only place for him to go was down.

Chris is right, in terms of recent precedents, and if that bothers Democrats hoping for a gigantic Obama landslide, it should be comforting in case McCain catches a break and moves ahead between now and November 4. The probability of any particular electoral outcome is not that far outside the MoE of most polls. It will likely be a close race, in popular votes at least, no matter what happens. And that’s why all the Obama campaign’s tactical advantages in money and the “ground game” may matter so much. But Democrats should avoid getting too caught up in either the highs or lows of the polls.