The bizarre siege is over, and a certain amount of mutual, if muted, congratulation is going on. All the victims save young Robert Dean Stethem, who lies in Arlington Cemetery in a martyr's grave, are free to go home, and the last of the burbling interviews, even those with the families hired by the networks, will be coming to an end.

There has been nothing like it in the history of terrorism. The Amal Shiites, for two unbelievable weeks, came close to making terrorism folksy.

John L. Testrake, the pilot of TWA Flight 847, called it "a learning experience." So did Jeffrey Ingalls, a close friend of Stethem.

And in fact, once the initial horror of Stethem's murder had passed, the whole episode took on the surreal coloration of some kind of exchange program, a seminar in U.S.-Mideast relations, conducted under the gun. Apparently, after long bull sessions on religion and politics, both sides came away with a new appreciation of the other fellow's point of view.

And what did the rest of us learn from the experience? Perhaps nothing that we did not know before.

We knew, for instance, that Ronald Reagan is the luckiest politician alive. Jimmy Carter spent 444 days on Calvary with his hostages; Reagan was in the clear after 17 days. Carter drew militant Moslem fundamentalists who wanted to shake the world; Reagan got Lebanese Shiites who seem to have taken courses in public relations, and who had a specific demand that could be met by Israel, our ally and client.

We also discovered again the awesome power of television. The Amal Shiites had figured out that TV sanctifies people for Americans. By showing them on the home screen, over lunch at a seaside restaurant in Beirut, attending a last supper with their guards and kissing their captors goodbye, the terrorists personalized the players and restricted Reagan's options. The Amal Shiites craftily made the hostages into members of the national family. Carter's hostages were kept in dungeons; their families agitated endlessly against their relatives being forgotten.

At the outset, Reagan was being importuned to take the hard line by other television luminaries such as Henry A. Kissinger and George Will; to put "national interest" over the mere saving of lives. The battle, if there ever was one, was finished once the first mad news conference flashed on the box. The Amal Shiites had turned the hostages into television celebrities, and Americans take television celebrities seriously.

Hostage spokesman Allyn B. Conwell was made for television. He has light eyes and regular features, and looks something like J.R. Ewing. Conwell could have been the hero of a daytime soap: earnest, troubled, articulate -- and with narrow interests of his own.

He made statements that caused a certain flinching at the highest levels of the administration and prompted a spate of expert comment about the "Stockholm syndrome," a phenomenon in which hostages come to identify with their captors rather than with the people who are trying to free them.

But you don't have to be a hostage to urge the Israelis to release the 700 Lebanese prisoners, mostly Shiites, in Atlit. Indeed, it is official U.S. policy that the prisoners are being held illegally.

But when Reagan and Secretary of State George P. Shultz belatedly attempted to include the seven "forgotten hostages" in the deal they vigorously denied they were making, Conwell protested. He was perhaps reflecting his own self-interest rather than the Stockholm syndrome. Amal leader Nabih Berri had, at best, a tenuous hold on the Shiites he could see, and none on those out of sight. And Conwell apparently had no compasssion left over for his unfortunate, untelevised brother-American captives, who are God knows where. In his Damascus news conference, he said he and his group were praying for the liberation of the Shiites, "if they're innocent people being held illegally."

Reagan acquired a new best friend in the Mideast, Syrian President Hafez Assad, a rather sinister figure he used to think of as an agent of terrorism and a Soviet puppet. Reagan had to give up on the seven forgotten victims. He had to back down on "no deal." He made no visible progress against international terrorism. But he will call it a victory, stoutly aver that Israel's plan to release 300 Shiites about two days after our hostages were flown to Frankfurt, was sheer coincidence. If he says it often enough on television, he will be believed.

The made-for-TV hostage crisis has shown us that the box is the real source of truth and power in the world.