Some of Senator Obama’s first comments on the governor of Alaska, Sarah Palin, were: “John McCain’s new veep nominee seems like a very engaging person, a nice person. But I’ve got to say, she’s opposed — like John McCain is — to equal pay for equal work. That doesn’t make much sense to me.”

Does Mr. Obama, once a student president of the Harvard Law Review and later a teacher of law at the University of Chicago, not know the law?

Women have had a legal guarantee of equal pay for equal work since the Equal Pay Act of 1963, and have the right under that Act to sue employers.

Can the Democratic candidate really be this clueless about such an important anti-discrimination statute?

Or, perhaps Mr. Obama does know that women have a statutory guarantee of equal pay for equal work, but wants to change that to equal pay for equal worth. That has been the more sweeping, and nebulous, formulation of some feminists.

A difference of two letters, if written into law, would open a new regulatory exercise, one that seeks to compare jobs traditionally held by women — teacher aide, librarian, dental hygienist — to jobs traditionally held by men, such as electrician, auto mechanic, and truck driver. It asks, essentially, whether a home health aide should be paid as much as a snowplow driver.

“Equal worth” would spawn immense opportunities for trial lawyers, who have contributed millions to the Democratic 2008 campaigns, as well as past Democratic elections.

Mr. Obama, embracing the misleading metric that women make only 77 cents for every dollar paid to men, cosponsored two Senate bills in 2007, neither of which has come to a floor vote.

The pending Fair Pay Act of 2007 calls for equal pay for “equivalent” jobs. The Fair Pay Restoration Act, better known as the Lilly Ledbetter Fair Pay Act, which passed the House in July 2007, would give plaintiffs in pay-discrimination disputes virtually no deadline to sue.

Both bills would expand the power of government and the courts over employers, embroil them in complex lawsuits, and discourage the hiring of women.

The Fair Pay Act would prohibit employers from paying women in female-dominated occupations salaries different from those paid men in male-dominated occupations, unless “a differential is based on a bona fide factor … such as education, training, or experience … “

This variant of “comparable worth” would require the Equal Employment Opportunity Commission to define male- and female-dominated occupations and review wage reports of firms with more than 25 employees, including information about the sex, race, and national origin of employees, for each wage rate in each job classification.

As any employer knows, the paperwork required would be a ruinous burden. Employers are supposed to be indifferent to race and national origin anyway, and may be prohibited from inquiring into those matters.

The Lilly Ledbetter Fair Pay Act would create an extraordinary new set of rights for plaintiffs in employment disputes. For the first time, employers would typically face no time limits on when suits may be filed, a legal status generally reserved for crimes such as murder.

This would be a radical change from present law because employees could argue that their current compensation flows from discriminatory decisions made years back. An employee could even sue a previous employer whom she left many years ago. This would generate massive lawsuits against current and former employers.

Mr. Obama’s statement that women are paid 77% of what men earn comes from outdated Census Bureau calculations that compare full-time median annual earnings of all women with those of all men. This is a spurious comparison. It does not take into account differences in education, job responsibility, years worked for an employer, occupation, hours worked in a year, and time in the workforce.

Lower pay can reflect decisions — by men and women — about field of study, occupation, and time in the workforce. Those who don’t finish high school earn less. College graduates who major in humanities rather than the sciences typically have lower incomes, and more women than men choose humanities majors. Many women take time out of the workforce to stay home with children, or choose jobs with shorter hours.

An economics professor at Baruch College, June O’Neill, analyzed data for men and women on demographics, education, work experience, children, and scores on the Armed Forces Qualification Test. When such differences are accounted for, men and women earn about the same.

When Mrs. Palin became governor, she did not receive 77% of her predecessor Frank Murkowski’s salary. She knows better than anyone that it takes skill and perseverance to get to the top of the career ladder. Ratcheting up litigation is no substitute.

Ms. Furchtgott-Roth, former chief economist at the U.S. Department of Labor, is a coauthor of “Women’s Figures: An Illustrated Guide to the Economic Progress of Women in America.”