The folly and the misery of Lebanon have not waned in the last few months. But there are fewer Americans here to see it and fewer still to report it.

The Israeli invasion of 1982 and its aftermath brought American troops and American diplomats and droves of American reporters. Just a year ago President Reagan said, "We have vital interests in Lebanon."

But now the American soldiers are gone. The diplomatic presence is greatly reduced. Of about 1,200 U.S. passport holders here, according to diplomats, those who are not of Lebanese descent number perhaps 250. And where once there were 72 American journalists, now there are nine.

Bombings, murders and kidnapings, a nearly total breakdown of authority and lawlessness that feeds on itself, combined with a rising mood of anti-Americanism among Shiite Moslem activists and continuing threats by the spectral "Islamic Jihad," have helped convince many American reporters that the story is no longer worth the risk.

As they leave, this city so long in U.S. headlines may run the risk of becoming, like Saigon or Phnom Penh or Tehran before it, largely invisible to Americans because the American press finds it impossible to work here.

Diplomats facing the same perils react similarly. "Our inability to move around safely means that we're accomplishing almost nothing here," one European diplomat who now carries a gun told a remaining American staff member of The Associated Press this week. "People won't even go out to dinner anymore. If you don't have a home video, you're lost."

In trying to explain why Beirut is perceived as more hazardous now than during Israeli air strikes in 1982 or the of the civil war that began in 1975 and now appears to have been only briefly interrupted by the Israeli invasion, one U.S. correspondent said: "We have become the story -- by virtue of our passports."

As the Reagan administration dramatically has devalued the U.S. interests in Lebanon that were once considered vital, editors and correspondents increasingly weigh the real dangers of staying here against the stories that must be done under extremely hazardous conditions.

"I don't mind waking up in the morning and having a story in Beirut. But to face death and have nothing?" was the question one hardened war photographer who made his name here asked himself.

"If the Americans were more involved, it would be much harder to leave," according to Larry Pintak, Middle East correspondent for CBS.

"The U.S. government has the blessed ability to develop passing interests in countries, and while it does, it's a hot story -- threats or no threats -- but the story has moved on," said Lucy Spiegel, the bureau manager of CBS.

Jeremy Levin, the Beirut bureau chief of Cable News Network, was kidnaped March 7 and is still missing. On Sept. 29, British Reuter correspondent Jonathan Wright was abducted while covering the aftermath of an Israeli raid in central Lebanon. He was freed 21 days later after an attempted escape.

But Lebanese society is breaking down and random, utterly unpredictable crime is as much a threat, and as debilitating, as political attacks.

Soldiers charged with keeping the peace are helpless in the face of heavily armed militias and criminals. One Lebanese Army private on the airport road told of seeing a militia unit stop a car and drag away its driver while he stood by doing nothing.

On Dec. 29 three journalists walked into a robbery at a French restaurant in mainly Moslem west Beirut. They were taken to their apartments, where cameras and money were stolen and one of them, Steve Hagey, bureau chief of United Press International, was held for several hours and beaten before he was released. His abductors later demanded $10,000 in return for his U.S. passport. Hagey has left the country and has not been replaced.

In the restaurants and shopping districts where once it was possible to find some haven from the fear and violence there are now constant reminders of encroaching anarchy. The elegant shops of Hamra Street are little armed camps, their owners fearful of thieves and frequent bombings. A Lebanese businessman driving nearby was stopped recently by a man who put a gun to his head and ordered him, "Take me to work, I'm late."

A neurologist at a west Beirut hospital complained that a local militia controls the scheduling for brain scans.

Two reporters dining at the popular Smuggler's Inn restaurant a few weeks ago were surprised to see a mouse. One of them joked with the waiter that it might get in her soup. "At least it's not carrying a gun," said Abed, the waiter. Abed was killed a few nights later when the restaurant was bombed.

Those reporters who have opted to stay, even the most daring, are exercising more caution. Jogging on the sea-front Corniche is out. Indoor exercise, video recorders and "Trivial Pursuit" are in.

"Everybody here has taken risks, but the risks are exhilarating when it is part of the job and it comes out in a story you think is important," said Gerald laBelle, 42, the Middle East news editor of The Associated Press. He said he has stopped walking to work, though it used to give him a feel for the place.

John Borrell of Time magazine admits that he worries about going to daily Arabic lessons because he does not want to set a routine.

"I wouldn't mind Beirut if there was a story. But one day you are going to walk into a street fight or car bomb. It's like sitting on top of an iceberg waiting for it to melt, and one day you're going to be in the water," Borrell said.

"It's not as predictable now. One can't tell which militia is in control of which end of the street," said John Kifner of The New York Times, who has covered Lebanon and the Middle East intermittently since 1979. "Before, it was clear that all factions, across the board, respected the idea of the journalist as a separate, protected entity. Now, it's not entirely clear that is true."

Last October, menacing statements by the shadowy Islamic Jihad coupled with a report from the State Department diminished any conviction that journalists were less likely to be targets.

It was a month after the suicide bombing attack on the U.S. Embassy annex in September when a U.S. public affairs officer called American journalists and told them, "American journalists in Lebanon face the same dangers that officials do, and we urge you to be careful, especially in Beirut." But western security officials connected with the U.S. Embassy assured many reporters there was "no new threat" that singled them out.

"A lot of us stayed because it had the ring of Washington trying to scare us out because no one wanted us here before the elections. We've stayed through innumerable wars, shelling, Israeli bombings, and we'd be damned if we were going to be driven out by our own State Department," Pintak said. "But we looked around and many had left; the odds were not with us."

The latest direct threat came from Islamic Jihad on Jan. 14. In a statement to foreign news agencies, an anonymous caller said five Americans being held will be tried as spies. Those people using journalism, education and religion for cover are agents in the CIA, the caller said. They have exploited the hospitality accorded to them to persist in their subversive activities and will get the punishment they deserve, he warned. CNN's Levin is one of the five Americans the organization said it holds captive.

Before 1975 and perhaps through most of the past nine years, Lebanon's climate, the Mediterranean, fancy boutiques and a wide selection of good restuarants lured correspondents into Beirut.

"No one can claim Beirut is a place to relax now," said Chris Drake, the Beirut bureau chief of NBC.

Some news organizations have started setting up shop in Jordan. The Palestinian story has shifted there, and the presence of Arab embassies in Amman helps justify the move.

The Associated Press has not pulled any of its American staff out. "We're nervous, but we just don't like to run out," laBelle said.

LaBelle, who suffered a shrapnel wound in the head last year while covering a gunfight, insists he does not regret coming to Lebanon. "You keep yourself going by thinking you'll put it all in a book, which you know you'll never write," he said.