From Erika Bolstad in Washington D.C. --

Former Alaska Gov. Sarah Palin's 40 percent favorable rating is the lowest for her since she shot to national prominence following the 2008 Republican convention, Gallup reported today. Gallup's poll looks at the slide in popularity of political figures, including former senator and presidential candidate John Edwards of North Carolina.

"Palin became a bit of a sensation after John McCain tapped her as his running mate last August," wrote Gallup's Jeffrey M. Jones. "But over the course of the campaign, her image suffered, going from a 53 percent favorable rating immediately after the 2008 Republican National Convention to 42 percent by the end of the campaign.

It doesn't seem to have hurt her potential book sales -- Palin's "Going Rogue: An American Life," due out Nov. 17, is No. 2 on Amazon. Her publisher has ordered 1.5 million copies printed and "is teeing up a major promotional schedule," reports the Wall Street Journal.

As for her political future? Gallup's take: "Palin could compete for the 2012 nomination because she is still widely liked by Republicans -- 69 percent have a favorable opinion of her while only 25 percent view her unfavorably," Jones wrote. "But she may have difficulty succeeding in the general election, given that Democrats have overwhelmingly negative opinions of her, and independents view her more negatively than positively."