Americans view first lady Michelle Obama in very positive terms as she hits the campaign trail on Wednesday.

Nearly two-thirds of U.S. adults say they approve of the way Obama is handling her position as first lady, part of the personal popularity that makes her an "invaluable asset," according to the White House.

Sixty-five percent of Americans said they approve of the way the first lady is handling her job, according to a CNN/Opinion Research poll released on Wednesday, compared to 25 percent who disapprove of her work. Ten percent had no opinion.

Obama's personal popularity doesn't necessarily distinguish her from previous first ladies whose own approval ratings were better than their husbands. But her husband's White House is looking to leverage that popularity to help Democrats at a pivotal point in the mid-term campaign season. 

Democrats are campaigning and fundraising furiously to hold off the kind of losses that could hand over control of Congress to Republicans.

The first lady will headline a fundraiser on Wednesday in Milwaukee for Sen. Russ Feingold (D-Wis.), and then travel to a fundraiser in her hometown of Chicago for Alexi Giannoulias, the Democratic candidate for President Obama's former seat in the Senate.

Later this week, Mrs. Obama will campaign for Sen. Michael Bennet (D-Colo.), who's avoided appearing with the president, and she'll appear with her husband at a rally on Sunday in Ohio.

"I think she is an invaluable asset to this White House," White House press secretary Robert Gibbs said of the first lady's appeal at his press briefing on Tuesday. "I think she has ... a story to tell about herself and her family, and I think she will tell that story and what the administration and some of these candidates have been able to do to help the families that they represent."

Michelle Obama has suffered some occasional missteps since moving to Washington. Her trip to Spain in August with daughter Sasha and close friends drew criticism for its hefty price tag. Her campaign for better childhood nutrition and increased exercise has also sometimes been criticized as nannying by conservative blogs, who have noted the president's occasional but highly-publicized jaunts to fast food joints.

But the First Lady has appeal across most demographics, according to Wednesday's poll. The CNN results found she had net-positive ratings with both men and women, white and non-white Americans, and adults in all age and income groups.

Even half of conservative voters said they approve of the way she's handled her job: 50 percent of self-identified conservatives approved of the first lady, while 38 percent expressed disapproval. (Her opinion is worse among self-identified Republicans, who disapprove of her 39-46 percent.)

The CNN poll, conducted Oct. 5-7, has a three percent margin of error for Mrs. Obama's general approval rating. It has a 4.5 percent margin of error among self-identified conservatives, and a six percent margin of error among Republicans.