The emergence of the presidential couple is one of the most important and contentious developments in America's postwar political history. After the exceptional Roosevelts, the change began innocently enough, with Mamie becoming the first First Lady to remain on the campaign trail without her husband - receiving nothing but praise as a result. By the 1960s, with Lady Bird lobbying for legislation on TV, the first signs of protest appeared.

In the 1970s, when Jerry and Betty Ford increased East Wing staffing and press coverage, the idea of the presidential couple was institutionalized, but Betty became so controversial she may have cost Jerry his chances for election. With Hillary Clinton, the backlash can no longer be denied. Though Bill announced during his first campaign that the country would be getting "two for the price of one," by his second he and Hillary appeared to have learned a painful lesson.

She had morphed into Nancy Reagan, speaking out for children's issues, loyally supporting her husband, and denying any interest or role in policymaking.

As Gil Troy points out, the most successful recent couple has been the Bushes, who modeled themselves after an older generation. The lesson is clear: First Ladies can be far more helpful than ever before with image-making, but not with substantive legislative or managerial functions. The country does not want an un-impeachable, un-removable partner to take a politically active role.