WHY IS OUR president, almost alone among Americans, unable to rejoice in the splendid outcome in the Philippines?

He has had a terrible time with the explosion of democracy which resulted in the triumph of Corazon Aquino, the "housewife" heroine of one of the century's great political dramas.

Has he picked up the phone to offer congratulations? No. Cory Aquino got calls from the Pope John Paul II and Indian Prime Minister Rajiv Gandhi, but none from the White House.

When asked if the leader of the western world had telephoned freedom's newest star, White House spokesman Larry Speakes replied stiffly, "He has not called President Marcos or President Aquino."

This is an echo of the startling even-handedness the president mysteriously displayed throughout the stirring clash between good and evil at the ballot box. While the violent fraudulence of the Marcos forces was in full view, the connoisseur of democracy in the White House saw only "evidence of a strong two-party system."

He subsequently made another ding-dong statement insisting there was cheating on both sides, a misstatement so blatant that Sen. Richard Lugar of Indiana, the Republican who led a monitoring mission to the Philippines, felt obliged to correct him publicly. When, finally, Reagan was forced to repudiate the rigged election, he did so in a statement drafted by his aides.

The president was asked at a White House press breakfast last Wednesday if he planned to stop off and see the new president on his way to the Far East economic summit.

"No," he said coolly, "I don't think there are any plans for us to do anything except go directly there."

At the same gathering, he expressed a minority view about Marcos the looter. Reagan sees instead a prudent investor: "The information I've always had was that he was a millionaire before he took office."

In the present acrid fight over military aid to the Nicaraguan rebels, the Filipino analogy brings up questions about why the supposedly freedom-mad Nicaraguans are not boiling through the streets. The president says protesting is too dangerous in that country -- as if Marcos had never imprisoned dissidents.

We may have to look for clues to this odd loyalty in his political past, which has milestones for him less visible to the rest of us. One thing we know: He recoils from comparisons with his despised predecessor, Jimmy Carter. Nothing he does must recall his rival. For him, the campaign of 1980 has never stopped. In his last State of the Union address he opened with a strong reminder of the miseries of life in the Carter administration.

But events have forced him to do what Carter did in 1979. Just as Carter finally abandoned the shah of Iran -- a move that eventually helped cost him the presidency -- Reagan has had to give up on the wooden-faced strongman in the Philippines. We do not know if he was personally fond of Marcos, whose charm escapes so many others, or whether he saw in the exit the collapse of the pillar of his foreign policy -- the theory that the most odious dictator presiding over a "stable" government is preferable to the risk of communism. The fact that Aquino is a splendid alternative brings him no pleasure.

Marcos' departure would recall the shah's, and nobody had been more vigorous than Reagan in denouncing Carter for failing a friend and an ally.

So in the lurid analogies being hurled about in the gathering debate over Nicaragua -- not to mention the red-baiting he has led and encouraged -- the president has been a little restrained about comparing Nicaragua to the Philippines. The fact that the comparison topples at the touch would not bother him -- this is a man who desegregated South Africa, do not forget.

The hint of what might be working on him finally bubbled up and out during a meeting with Jewish leaders. The president hit upon Valley Forge as his metaphor of choice. He called the contras "moral descendants" of George Washington's men -- although a recent dispatch from the front by Washington Post correspondent Robert McCartney illuminates a critical difference. The Latin Yankee Doodlers are sulking in their tents for lack of good boots. Washington's men wrapped their bloody feet in rags in the bitter winter, we were always told. Reagan's "Freedom Fighters" demand quality footwear.

The president then made the astonishing statement that without the $100 million he's asking from Congress, Nicaragua would become the "home away from home for Qaddafi, Arafat and the Ayatollah."

The Ayatollah? Is he a secret communist? The rest of us thought of him as an Islamic fundamentalist. He would be a soul-brother of Daniel Ortega?

It was a hint that Reagan has Carter on the brain.

The whole Filipino episode, wonderful as it was, suggests about our president that his mind is a darkling plain "where ignorant armies clash by night."