When Nancy Reagan and Raisa Gorbachev get together for coffee and the White House tour today, they'll have something in common to talk about, and it won't be their recipes for bread pudding. Tips on keeping your balance during a high-wire act would be more like it.

Both first ladies have become controversial in their homelands. Both, it would appear from news reports, are functioning against a backdrop of resentment, jealousy and pettiness. And both are emerging as people who wield enormous personal power in cultures where the very notion of powerful women is an oxymoron. As wildly different as the histories of the Soviet Union and the United States are, both societies are lurching along awkwardly toward a more egalitarian accommodation between the sexes. But neither is the least bit comfortable yet with having first ladies who are overtly, visibly, out-of-the-closet powerful influences on their husbands.

Nancy Reagan is a veteran of the balancing act that U.S. first ladies are faced with. Traditional older women gave her high marks when she arrived in Washington and devoted her considerable energies to redecorating the family quarters and getting new china. She set a lot of other people's teeth on edge. She played the role of traditional wife and swiftly became one of her husband's political liabilities. In more recent times, another Nancy Reagan has emerged: this one is the all-powerful woman running the show while a confused and enfeebled president dodders around the White House looking for his slippers.

Open season got declared on this Nancy Reagan when she did what nobody else seemed able to do, namely engineer the coup de staff in which Donald "Throw Weight" Regan returned to his first love, the private sector. New York Times columnist William Safire called her a "power-hungry first lady," and wrote that the president was being "weakened and made to appear wimpish and helpless by the political interference of his wife."

On the eve of the signing of the Intermediate-Range Nuclear Forces Treaty, apoplectic conservatives, who are turning purple over the possibility that something was about to happen that might prevent Armageddon, took up the Safire refrain. That great American, Howard Phillips, who is chairman of the Conservative Caucus and cochairman of something called the Anti-Appeasement Alliance, offerred this insightful analysis of how Reagan came to sign the INF Treaty: "Ronald Reagan is a very weak man with a strong wife and a strong staff. He becomes a useful idiot for Kremlin propaganda." The very thought of a strong first lady short-circuited the sector of Phillips' brain that controls his manners.

Right about the time that Regan was returning to the private sector, The New York Times reported that Nancy Reagan had told friends "she plans to focus her attention on seeking an arms control agreement with the Soviet Union." That is precisely what is happening nine months later.

According to the manuscript of a book by former White House aide and Reagan confidant Michael K. Deaver, Mrs. Reagan pushed her husband into his first summit with Gorbachev. She was also the force behind a purge of hard-liners.

The evidence is mounting, in other words, that Mrs. Reagan can do a great deal more than pour a cup of tea.

Now comes the news that the same applies to Raisa Gorbachev. Her husband told the entire world (the entire world, that is, except the Soviet Union), via American television that he discusses "everything" with his wife. The Moscow censors apparently thought that this was simply too much for the folks at home in the motherland to handle so it was deleted in that broadcast. Glasnost has its limits.

But the damage has been done. Both women have been revealed to be real wives -- the kind of people their husbands confide in and trust, and that gives them enormous influence and power. It goes with the territory. Pretending otherwise is hypocritical or naive -- or both.

There can't be a much lonelier job than being a head of state. In the United States, for example, anyone close to a head of state automatically qualifies for a six-figure advance on a tell-all book. The first lady is the one person the president can trust to be always on his side. She's not thinking about her next job and she's not beholden to special interests that got her a Cabinet post. She's the one person who can be a critic without getting fired. She can be a stabilizing influence.

Mrs. Gorbachev and Mrs. Reagan seem to be very much part of a team. Their husbands not only acknowledge this, but they also appear to treasure what their wives do for them. Their countrymen ought to, as well.