Forty years ago, when Ronald Reagan was a liberal Democrat struggling to reestablish his film career, Republicans captured control of Congress and proceeded to avenge themselves on the ghost of President Franklin D. Roosevelt.

What the Republicans did was pass the 22nd Amendment limiting a president to two terms in office. Approved in 1947, it was ratified four years later and immediately became the principal constitutional illustration of the law of unintended consequences.

In 1952, the popular Dwight D. Eisenhower was elected to the first of two presidential terms, prompting Democrats to quip that Republicans had aimed at Roosevelt and hit Eisenhower. It was conventional wisdom among constitutional scholars at the time that the amendment had unwisely restricted executive power, in effect making the president a political "lame duck" after his reelection.

This year, those scholars were joined retroactively by President Reagan, who says he was "in perfect agreement" with the 22nd Amendment when he came to the White House. In fact, Reagan liked the two-term limitation so much that he unsuccessfully attempted to impose it on future governors during his eight-year tenure as governor of California.

Now, with history closing in on his presidency, Reagan has changed his mind. In an interview early this year with The Washington Post, he identified a principal political defect of the amendment, saying that "the minute the '84 election is over, everybody starts saying, 'What are we going to do in '88?' and focusing a spotlight" on potential presidential candidates. Subsequently, in an interview with Barbara Walters, Reagan said that "in thinking about it more and more, I have come to the conclusion that the 22nd Amendment was a mistake."

Echoing the arguments of the Democrats who tried in 1947 to prevent a unanimous Republican majority from passing their vengeful amendment, Reagan said, "Shouldn't the people have the right to vote for someone as many times as they want to vote for him? They send senators up there for 30 or 40 years, congressmen the same."

Some enterprising Democrats with a sense of history should take the president at his word and try to repeal the amendment, comfortable in the knowledge that it could apply only to future presidents. They would be on sound constitutional ground.

As Rep. John W. McCormack (D-Mass.) put it in opposing the amendment at the time of passage: "The framers of the Constitution considered the question and did not think they should tie the hands of future generations. I don't think we should. Although Thomas Jefferson favored only two terms, he specifically recognized the fact that situations could arise where a longer tenure would be necessary."

Republicans contemplating the prospect of, say, a George Bush-Pat Robertson ticket may think that situation has arrived. And Democrats should be able to appreciate the frustration shared by those short-sighted Republicans of the 80th Congress, who mistrusted the people because they kept electing FDR.

Reagan is right in opposing the 22nd Amendment, even if his insight is illuminated by self-interest. After midterm elections this year, particularly if Democrats regain control of the Senate, Americans face the prospect of two years of divided government in which the president would lack the political leverage provided by the prospect that he might seek reelection.

The two-term limitation was discussed at length and rejected by the founders, who trusted the people more than the Republican majority of the 80th Congress did. Recalling this during the 1947 congressional debate, Rep. Joseph R. Bryson (D-S.C.), an ardent New Dealer, said that if the people could be trusted to elect a president for two terms, "they also can be trusted to determine whether he should be continued in office for a third term."

FDR would have been delighted with this argument and perhaps even more pleased with the endorsement of it by Reagan, a onetime disciple who by New Deal standards has gone astray. Now is a good time to get rid of an amendment that had as its principal motive a profound mistrust of the capacity of Americans to govern themselves.

Reaganism of the Week: Discussing the Challenger shuttle accident, Reagan said last Wednesday, "Maybe part of it was also due -- I've often wondered this -- if part of it wasn't due to the balmy climate of Florida and that it was difficult for anybody to believe that they'd had a cold snap that was -- that could render that O-ring dangerous."