In her unauthorized biography of Nancy Reagan, Kitty Kelley has said again what everybody knows but won't admit: The boss's wife is a woman with clout.

So why the surprise?Nancy Reagan is but one in a long line of women who have functioned as political brokers as well as social butterflies in the White House.

Abigail Adams, wife of John Adams, and Sarah Polk had strong working relationships with their husbands.

Mary Todd Lincoln meddled in her husband's Cabinet choices.

Edith Wilson was criticized for running her husband's administration after a stroke disabled him.

It was to Eleanor that FDR turned for political advice.

Jimmy Carter valued Rosalynn as an adviser.

And yet, despite the historical record, first ladies hide behind a veneer of domesticity. When they step out into the open, as Rosalynn Carter did by attending Cabinet meetings, the roof falls in.

The myth that a first lady doesn't have power is the most enduring and the most sexist myth in American politics.

Consider Barbara Bush. Like her predecessors, she is touted as a model for American women.

In 1988 she often said the best way to become first lady was to "marry well."

What's missing from this picture is that Mrs. Bush is a full partner in the family business of politics.

Barbara Bush acknowledges she is "very candid" with her husband about issues and staff members that trouble her. Political operatives respect her savvy.

Referring to the 1988 presidential election, Republican National Committee chief of staff Mary Matalin remarked that Mrs. Bush "understands the tactics and she understands the strategy."

Indeed, in 1988 Mrs. Bush was credited by Newsweek with encouraging her husband to run negative ads attacking Sen. Bob Dole's position on taxes.

The Constitution does not recognize the presidency as a dual office; women are smuggled into power with their elected husbands.

During the 1988 campaign I traveled with the candidates' wives and listened as reporters asked about how they influence their husbands' decisionmaking.

To liberals they explained that of course their good marriages allow them to discuss everything with their husbands.

To conservatives they said that of course their husbands made the final decisions.

Of course, that's not how things really work.

Thirteen women wanted to be first lady in 1988, among them, a former secretary of transportation, a former state representative, several lawyers and an author.

These women wanted to make policy, not tea.

How could they avoid the Nancy Reagan trap? How could they admit to advising their husband without damaging his prospects?

Smart women all, they had to play dumb.

Mrs. Reagan long pretended she married rather than helped create one of America's political leaders.

Post-mortems, such as Kelley's, contend Nancy Reagan wielded her derivative power covertly and perhaps even abused the public trust.

Still, Mrs. Reagan wasn't the first president's wife to be a major player in the national political game.

Until America figures out what to do with first ladies, she won't be the last.