First lady. First mom. Mom in chief. No — none of these titles works. And therein lies the problem.

When Michelle Obama moves into the White House, she will inherit a title with no job description as the world watches to see how she performs. So far, media coverage has focused on what she will not be doing — she is taking a sabbatical from her paid career. Obama has described her major role upon entering the White House as that of a mother wanting to help her daughters adjust to their changed lives as children of the president of the United States.

Media reports have focused on her Ivy League pedigree and her distinguished career as a lawyer and hospital administrator. By giving up her paid position, the argument goes, she has relinquished the opportunity to be the role model in chief for working mothers. But this thinking underestimates the intricate role of first lady, which will call on all of the skills she has developed as a working professional.

The very debate about whether Michelle Obama is sacrificing her career shows that we must develop a proper perspective about the position of first lady, including a job description for the spouse of the president. Surely the person in one of the most visible roles on the planet deserves a proper title and salary to go along with the intense demands of this most nebulous position, which is, in essence, a job.

Since our nation has yet to elect a female president, let's focus on the historic title of "first lady." Since George Washington's time, the one widely accepted function of the role has been that of hostess, presiding over the considerable social and ceremonial events that take place at the White House. When the unmarried James Buchanan became president in 1857, he took his 27-year-old niece with him to the White House to serve as official hostess.

It has become traditional, though, for the first lady to reach far beyond hostess duties. Lady Bird Johnson presaged the environmental movement with her national focus on highway beautification. "Just Say No" became the rallying cry for Nancy Reagan's efforts to prevent substance abuse. And Laura Bush has undertaken a variety of causes, including literacy, education, and women's health and wellness; she has also used her international visibility to speak out against the oppression of women.

Yet the lack of clear definition of their role has resulted in first ladies facing a web of conflicting expectations. Betty Ford was criticized for her strong advocacy of women's rights, including her support of the Equal Rights Amendment and abortion rights. Yet she was beloved for her courageous battle against breast cancer and her successful fight against alcohol and prescription drug addiction. When Rosalynn Carter sat in on Cabinet meetings as her husband's protective observer, the public reaction was negative, notwithstanding the intensely close relationship she and the president shared. She served with distinction, however, as the honorary chairwoman of the President's Commission on Mental Health and drew international attention to the plight of refugees in Cambodia and Laos.

As the first lawyer to serve as first lady, Hillary Rodham Clinton encountered controversy and conflicting signals over how best to use her skills and energy in the White House. She was given the unprecedented role of leading her husband's Task Force on National Health Care Reform but was widely criticized when it failed. Yet her activism in support of her husband's agenda and her frequent international travel became the model for the modern presidential spouse.

With another highly credentialed spouse preparing to enter the White House, it is time to negotiate a clearer role for the first lady — one that has a job description and a salary appropriate to the range of responsibilities that come with being the president's spouse. Compare the responsibilities of the nation's first lady with those of the spouse of the president of a major university. Increasingly, colleges and universities are compensating their first spouses for the enormous contribution of time and talent these people devote to their role. The Association of American Universities has even adopted guidelines that urge governing boards of universities to recognize the spouse's role and to consider a titled position with a job description and salary and/or benefits. Certainly the spouse of the U.S. president deserves no less.

Michelle Obama has impeccable credentials that will not be diminished by her decision to discontinue her paid work outside the home. Like other first ladies before her, she will have an office, a staff and even a budget. What other positions with staffing and budgets have no job description?

It is only fair that the role of first lady be formally recognized for the demanding position that it is. Then we can stop the false argument about whether Obama has "opted out" of the workplace, knowing that she is about to begin the hardest job she will ever hold.

Lauren Stiller Rikleen is executive director of the Bowditch Institute for Women's Success. She wrote this commentary for The Washington Post.