Poll: Obama's sinking numbers starting to drag down Michelle Obama

White House historians point to a fundamental difference in how Americans view the wives of Republican and Democratic presidents. Laura Bush, for instance, kept very high approval ratings, even as her husband’s tanked, because she maintained a separate identity and was viewed as a traditional first lady who didn’t meddle in Oval Office affairs. McBride said her staff didn’t conduct polls but instead looked at issues of the day to see where the first lady could make a difference without running into trouble.

But with Democratic first ladies dating back to Eleanor Roosevelt, historians said, there is an expectation that the president and first lady are a package deal – a bargain enthusiastically embraced by the Clintons, who overtly campaigned as a twofer.