At rallies in the week following the convention, the McCain-Palin duo saw their best attendance and a newfound zeal, and the Republican ticket took the lead in national polls for the first time.

But polls show that the momentum has shifted once again.

Palin's favorable rating is at 40 percent, according to a CBS News/New York Times poll. That's down 4 points from last week. Her unfavorable rating is at 30 percent, rising 8 points in a week.

The poll was conducted September 12-16 and has a sampling error of plus or minus 3 percentage points.

Former Bush adviser Karl Rove predicted Wednesday that Palin's star power would wear off.

"Nothing lasts for 60-some-odd days," Rove told The Associated Press. "Will she be the center of attention in the remaining 48 days? No, but she came on in a very powerful way and has given a sense of urgency to the McCain campaign that's pretty remarkable."

But this week, the Democrats recaptured the headlines, and Obama regained his lead in the national polls.

CNN's latest poll of polls, out Thursday afternoon, shows him ahead of McCain by 3 points, 47 percent to 44 percent.

The poll of polls consists of six recent surveys: CBS/NYT (September 12-16), Quinnipiac (September 11-16), IPSOS-McClatchy (September 11-15), Gallup (September 15-17), Diageo/Hotline (September 14-16) and American Research Group (September 13-15). It does not have a sampling error.

After a week in which McCain put Obama on the defensive over allegations of playing the gender card, the economic crisis has given Obama an opportunity to go on the offense. Most Americans see Obama as more capable than John McCain when it comes to handling the economy, polls show.