Michelle Obama – who dispenses giant bear hugs with aplomb and has stood for hours surprising tourists at the White House with the first dog, Bo, by her side – appears anything but reserved. She dishes family tales at events, telling supporters in Virginia about her humble roots growing up in a “little bitty apartment” on Chicago’s South Side, and how her mother hasn’t changed a thing.

“My room is the same,” she said to laughter. “Same bed sheets, same pictures.”

She boasts of her husband’s accomplishments, ticking off passage of the health care law, reversal of the military’s “don’t ask, don’t tell” policy on gays, the appointment of two women to the Supreme Court and his promise to withdraw troops from Iraq.

And she vouches for his character, referring to him repeatedly as Barack and introducing him to the audience as a doting father, as well as the son of a single mother: “I have to admit I’m a little biased about our president.”

She never mentions Romney by name or uses the word Republican as she implores volunteers to get working.

“Multiply yourselves!” she exhorted the crowd in Virginia last week. “Reach out to your friends, and your neighbors, and your colleagues, and your congregation members, and your social club members, and the other ladies you have tea with, and the people you walk with in the morning, and the yoga people, and the people in the grocery store line. Convince them to join you in giving just a little part of their lives each week to this campaign.”

The White House controls the first lady’s image carefully, focusing on her role as a mother, friend of military families and advocate of nutrition and fitness: Her basketball-playing husband recently joked that she can outdo him in pushups.

Through campaign appearances and a TV and radio publicity blitz around a new book on the White House garden, she stays tightly on message, something other Obama campaign surrogates haven’t managed to achieve.

Newark, N.J., Mayor Cory Booker and former President Bill Clinton were forced in recent weeks to step back from remarks that appeared to question the campaign’s strategy of criticizing Romney’s business record. The first lady faced a similar dustup in 2008, when critics used her remark on the campaign trail that “for the first time in my adult lifetime I am really proud of my country” to portray her as angry or unpatriotic.

This time, Michelle Obama stays clear of divisive politics. Her stump speeches are long on cheerleading and devoid of partisan attacks.

And although many of those waiting outside the hall in Philadelphia were familiar with her anti-obesity stand, including working with Walt Disney World to improve nutritional standards, she doesn’t bring up her role as first lady at political events.

She’s worked to tamp down politics in that official role: After she initially said nice things in an interview about New York Mayor Michael Bloomberg’s efforts to ban big servings of sugary drinks, her office issued a statement that said she wasn’t taking a stand on the controversial effort.

When a Democratic strategist said that Ann Romney, a stay-at-home mom, had never worked, the first lady weighed in on the kerfuffle, with a carefully crafted tweet that offered no offense: “Every mother works hard and every woman deserves to be respected.”

Republicans suggested that she’s pointedly taking the safe route.

“For a woman who has two Ivy League degrees to eschew any type of public policy voice suggests she’s being deployed mainly as a way to make him more relatable and accessible and to convince people that hope and change is alive and kicking,” said Kellyanne Conway, a Republican pollster.

“There’s just not going to be any ‘Michellecare,’ “ Conway said in a reference to Hillary Clinton’s controversial work on health care. “Michelle has taken the political versions of mom, baseball and apple pie, and avoided controversy.”

Republicans say there’s a limit to the first lady’s influence, and political analysts say voters aren’t swayed by those who aren’t on the ticket.

Voters such as Carol Nashleanas say differently. A Philadelphia retiree, Nashleanas considers Obama “the most significant first lady since Eleanor Roosevelt” for her work on childhood issues.

“She’s amazing,” Nashleanas said. “I’d vote for her.”