Nonsense, says Marc Ambinder. A true bounce lasts weeks; after three days, all we can call this is a blip. It’s true that they’re still tied in Rasmussen, but…

The latest three-day Gallup Poll Daily tracking average (Aug. 25-27) is directly coincident with the first three days of the Democratic National Convention in Denver, and is no doubt beginning to reflect the typical convention “bounce” that Gallup has observed in most party conventions in recent decades. There is a lag of sorts involved in the daily tracking; interviewing is conducted in most parts of the country before that evening’s high-focus speeches have taken place. Thus, the current three-day average would reflect any impact of Monday night’s speech by Michelle Obama, and Tuesday night’s speech by Hillary Clinton, but would not completely reflect Wednesday night’s lineup of speakers, such as John Kerry, former President Bill Clinton, and vice presidential nominee Joe Biden, nor the appearance on stage at the end of the evening by Barack Obama himself.

Last night was the strongest thus far and tonight will be even stronger, so if he’s already picking up points from Hillary nuts coming home and middle America warming to Michelle O, he’s in good shape. Especially given the bad vibes surrounding the GOP convention: There’s a hurricane on the horizon, pro-choice VPs in the mix, and an enthusiasm gap guaranteeing that the most of the airtime will be devoted less to building up McCain than tearing down The One. My hunch is our best-case scenario for mid-September is McCain still stuck at 45 but with Obama’s bounce destroyed by GOP attacks. Exit question: Too pessimistic?