Playing it safe can sometimes pay off, as first lady Michelle Obama is finding with some of the highest favorable ratings in official Washington.

And she could be taking those numbers out for a test drive, as the White House looks for ways to leverage her popularity without diminishing her value as an asset.

For the first lady, the key is finding a way to take a more substantive role in the administration, while still tending her kitchen garden and childhood obesity projects.

"People have been fabulous about this issue," the first lady said recently of her "Let's Move" campaign. "Our goal is to end the epidemic of childhood obesity in a generation."

While hula hoops on the South Lawn generate the most pictures and attention, Obama is using her popularity to push for better food labeling and legislation requiring restaurants to provide nutritional information about their food.

She also is aiming for improved school lunches and athletics programs, and has secured funding to locate healthy grocery options in neighborhoods without them.

A recent Gallup poll found Michelle Obama with a 66 percent favorable rating -- the top of a heap that included her husband at 52 percent, Sarah Palin at 44 percent, and Dick Cheney at 36 percent, among others.

Lately she has stepped up her profile with a visit to the Gulf Coast to highlight economic and environmental issues, and a preliminary foray into midterm politics.

She visited Haiti to generate interest in earthquake relief, and spends time supporting military families and visiting government agencies to thank federal workers, among other things.

So far, her efforts have been well received, although she generated some heat for exhorting Americans to vacation on the Gulf Coast, then taking her own family to a ritzy resort town in Maine.

The White House subsequently announced the Obama family will spend a weekend on the Gulf Coast in August.

"I think she is walking the tightrope between the very policy-oriented Hillary Clinton first ladyship and the hands-off politics of Laura Bush," said Katherine Jellison, an expert on first ladies at Ohio University.

It's a notable switch from just two years ago on the campaign, when Obama drew frequent criticism for her outspokenness, and Democrats fretted about whether she could be an asset to the president.

Since then, Obama has significantly softened her approach. The former high-powered lawyer and corporate executive is more often talking to magazines about her workout, her wardrobe, and family life.

Now, she may begin expending some of her capital on politics. So far, she has made an appearance with Senate Majority Leader Harry Reid and raised money for the Democratic National Committee. She is reportedly in demand by other candidates this fall.

But getting involved in politics is a touchy matter for a first lady -- Laura Bush did so sparingly, partly out of concern that appearing too partisan can diminish a first lady's effectiveness in other areas.

"Every day, across this country, so many women wake up every day and try -- using everything they have -- to make life a little better for others," Obama recently told a national gathering of Democratic women. "I feel hopeful."