The vacations. Few of Mrs. Obama's public moves have been widely labeled as gaffes, but a trip to Spain in the summer of 2010 dealt a brief blow to her otherwise steady popularity numbers.
A longtime Chicago friend was taking her daughter to Spain, and she asked Mrs. Obama to come with her younger daughter, Sasha. Despite warnings from advisers, she went, during the depths of the recession, during a week when 131,000 jobs were reported lost.
Although rules required her to reimburse the equivalent of first-class airfare, and her friends flew separately and paid for their own hotel rooms, taxpayers spent $467,585 on costs such as Mrs. Obama's jet, Secret Service protection, and food and lodging for accompanying staff, according to documents obtained by Judicial Watch, a conservative public integrity group.
When she traveled to Aspen, Colo., in February, without the president, conservative websites listed it as the Obama family's 16th vacation since taking office. (Opinions vary along political lines on how the Obama vacations compare to those of previous first families.)
Mrs. Obama's clothes also have been a target.
The Obamas are worth millions thanks to the president's best-selling books, and Mrs. Obama earned more than $300,000 in 2006 as a hospital vice president and board member. Although she makes a point of wearing inexpensive fashions from places like J. Crew and H&M, she has occasionally sported things like $515 Lanvin sneakers while volunteering at a food bank, and a $6,800 J. Mendel jacket at a Buckingham Palace reception with Queen Elizabeth II during the Olympic Games in London. (Not to mention the silvery, leather-esque jeggings she wore to the Kids Choice Awards).
All this comes on top of claims that she holds a grudge against America for its past racial sins.
On the campaign trail in 2008 she famously said: "For the first time in my adult lifetime, I am really proud of my country, and not just because Barack has done well, but because I think people are hungry for change."
The conservative National Review magazine quickly put her on the cover with the headline "Mrs. Grievance." The story made a claim that remains inseparable from her image on the right: "Michelle Obama embodies a peculiar mix of privilege and victimology, which is not where most Americans live."
Other than the obvious fact that she is the first black first lady, how does Michelle Obama, 48, compare with other presidential wives?
Hillary Clinton was another Ivy League lawyer with a high-powered career who stood on equal footing with her husband. But Mrs. Obama has shown no desire to run for office, and her beauty and style are essential to her image while Mrs. Clinton's appearance was often mocked.
Like Mrs. Clinton, Mrs. Obama is said to offer frequent advice to her husband, and is deployed often on the campaign trail to articulate and explain the president's beliefs. But Mrs. Obama has not been accused of meddling in policy, a perception that dogged Mrs. Clinton.
Jacqueline Kennedy? Like Mrs. Obama, she was seen as a glamorous, modern presence who brought change to the White House — but JFK never referred to his wife as "the boss."
Carl Sferrazza Anthony, a historian with the National First Ladies' Library, says Mrs. Obama shares something with Clinton, Kennedy, Betty Ford and Eleanor Roosevelt: Her public persona is very close to who she is.
"When in public, Mrs. Obama does not clip herself to the point of repressing her intentions or viewpoint," says Anthony, who has spent time with 10 presidential wives, from Mrs. Kennedy to Mrs. Bush. "She has defined herself by looking at how she could adapt the traditional roles of a first lady to her own personality."
That's what Mrs. Obama described in a conversation with reporters last February:
"Ultimately, the role has to be defined by the individual. Because not every first lady or first spouse is going to be me. They're not going to think like me. . Part of what I say to women, part of what we fought for is choice — not just one definition of what it means to be a woman."