Post-debate bounce?

According to a panel I watched last night on C-Span that included Rick Berke (Deputy Washington bureau chief of the New York Times) and several political science researchers, debates don't typically produce much of a bounce, and when they do, it can be temporary.

For example, in 1984 Ronald Reagan was widely assumed to have lost his first debate with Walter Mondale - who saw his poll numbers surge 7 points. But Reagan came right back and got a 7 point boost out of the second debate. However, now that the three debates are held so close together, some of the experts on the panel suggested voters may view them individually as just a part of the larger whole, implying that voters won't come to any final conclusions until after the last debate.

The panel also pointed out that debates can have a 'step effect' when a candidate gets a small bounce but it endures, and in fact they are able to expand the bounce as the election nears.

Democracy Corps., a left wing polling organization, did find Kerry gained a net 2 points while Bush stayed the same. A similar result is evident in many of the polls internals - favorability, the Iraq war and the war against terror - yet among independents Kerry surged and Bush actually lost ground. As Ruy Teixeira points out:

The critical bloc of Independent voters moved considerably toward John Kerry. Kerry's most notable achievement of the night was the vote shift among Independents where his vote increased 4 points from 50 to 54 percent while Bush’s vote dropped 3 points from 45 to 42 percent. Kerry’s favorability among independents jumped 12 points, and he addressed many of their concerns, both on security - up 10 points on making America safer and more secure, and 16 points on having good plans for Iraq - and leadership qualities - up 13 points on strong leader, up 10 points in having confidence in him, and a drop of 11 points on flip-flopping.

I suspect many post-debate polls next week will show miniscule improvement for Kerry among the horserace numbers - perhaps no improvement at all - but improvement in many of the internals, and perhaps in head-to-head state polls. But, if Kerry can keep it up, he has a real chance to emerge from the debates with an enduring lead, one that will be very hard for the President to counter with only 2 1/2 weeks left after the last debate.