Three things and maybe a fourth, says Laura van Assendelft, professor of political science at Mary Baldwin College in Staunton, VA and a scholar on the role of women in politics.
"The current expectations for the office of first lady are a continuation of the ceremonial duties of the job, making appearances at official functions and 'stand-in' speeches, and policy advocacy on non-controversial issues." Today, however, the role of senior advisor is also available to first ladies.
Dr. van Assendelft, co-author of the book Women, Politics and American Society and an editor of the Encyclopedia of Women in American Politics, says the role of the first lady has developed in much the same way as the role of the vice president. The job of the "veep" in the modern presidency also has evolved from ceremonial and "stand-in" functions to active policy adviser.
It remains to be seen whether the new first lady will push the boundaries of the office.
"Groundbreakers are criticized but they also expand expectations," she notes. "Lady Bird Johnson campaigned on her whistle-stop tour of the South and demonstrated how beneficial the campaigning spouse can be, at a time when the public was still deciding if this was appropriate behavior or not."
"Fast forward to 1996 when both Elizabeth Dole (wife of GOP nominee Bob Dole) and Hillary Clinton gave prime time speeches at their party conventions. Today if spouses do not enthusiastically take the campaign trail, we criticize them."
First ladies now are expected to be the most passionate and strongest supporters of their spouse's campaign.
Neither Michelle Obama nor Cindy McCain appears to be politically ambitious in the way that Hillary Clinton became a lightning rod for attitudes toward women and, in particular, how they might use "unelected power."
"Both Michelle and Cindy are filling the role of head cheerleader and neither is promising 'two for the price of one,'" notes Dr. Van Assendelft.
If Senator McCain wins the election, Dr. van Assendelft says that "Given Cindy's background, one would assume continuation of a role in world poverty issues, particularly emphasizing programs for children. She would have to decide what role to play in the Hensley Family Foundation much the way that Elizabeth Dole considered how her role in the Red Cross might change if she became first lady."
If Senator Obama wins, "Michelle might be equally likely to be the first first lady to work outside the home, given her professional background and passion for education and social issues," observes Dr. van Assendelft. "However, throughout the campaign she has emphasized her primary role as a mother—a role that will take more time to protect if she heads to the White House."