Like millions of Americans, Atlanta police officer Peacock had a flashback Monday afternoon, a kind of errie deja vu feeling that sent a shiver through him as he lay in the trauma ward of Grady hospital.

Peacock was watching his beadside television, recovering from his own wounds from a sidewalk shootout with two strangers the day before. Then he saw the president and his men fall.

"It's a spooky feeling to have been shot the night before, then watch someone else get it before your very eyes," Peacock said.

A lot of Americans, perhaps most of them, had flashbacks Monday. Dr. Ralph Abernathy started shaking uncontrollably as his mind flitted to the motel balcony where Martin Luther King Jr. fell at his side in 1968.

Rafer Johnson was ill with the flu, but he got sicker as his mind darted to the hotel hallway where he watched Bobby Kennedy gunned down two months later in that same bad year.

Others spoke of mind warps to a limousine in Dallas in 1963 or a sidewalk in New York just three months ago when John Lennon fell. Still, it was different this time.

The acts of violence were becoming so regular, so ingrained, so much a part of American life that the latest shootings -- even with a president involved -- left many Americans almost immobilized during the long day of televised irrationality when Reagan was shot.

There simply were too many other violent acts like the one that brought down Peacock, that killed 21 black children in Atlanta, that felled seven from gunshot wounds in New York on the same day the president was attacked. terms of anxiety about their own safety or dark depression over an inability to cope with the senselessness of it all.

Daniel Brackeen, a Dallas ice cream maker, acknowledged that the shootings triggered memories of 1963 and a slight defensiveness about his city's own dark day of assassination. But it was more than that -- shock then, numbness now.

"I was utterly depressed," Brackeen said. "I felt a deep lonely feeling in my stomach, like it was a personal attack. I was in a bad mood all day. I couldn't work. I didn't eat dinner. My children asked me why did it happen. They expressed amazement and wonder and I couldn't explain to them why."

Across the land, reactions ranged from the prayerful to the bizarre, from fatalistic to angry, from the kind of hopelessness that accompanies a sickness out of control to the sort of bitterness that wells up when the untoward happens one time too many -- and then happens again, and again.

"It's gotten to be old hat," Travis Powell of Atlanta said almost dully. "It's one more thing in addition to all the other bad things that have happened lately," said Mary Kerbaugh, ordering another drink at a bar in Harrisburg, Pa.

In Manning, S.C., Circuit Court Judge James Morris cited Abraham Waring for contempt of court after he allegedly broke into applause in the courtroom after the news was announced.

In Paducah, Ky., people gathered around the TV's in a downtown Sears store and stayed throughout most of the afternoon. "It's hard to believe the world is in such bad shape," a clerk said wanly.

In Seattle, nurses in the psychiatric ward of the city-county hospital said they could "feel" the depression level sink as patients, watching on color television, restlessly viewed the shooting over and over.

In Tokyo, former president Gerald R. Ford, target of two unsuccessful assassination attempts, said it was impossible to protect presidents against attacks by "loners, kooks, screwballs, whatever you want to call them."

In California, Reagan's daughter, Maureenm, was outraged at the acceptance of the vulnerability of American leaders. "This cannot, this will not, happen to another president," she said, raw anger rising in her voice.

In New York, Jack Newfield, an editor of the Village Voice and biographer of Robert F. Kennedy -- who had been 12 feet away when the second Kennedy was shot -- said his left-wing, anti-Reagan staff was "stunned and depressed." Then Newfield wandered off, like many people, into a sentence that wouldn't end:

". . . the picture of this kid Hinckley, he looked like [accused Lennon assassin Mark David] Chapman, like all of them, and you just begin to think of all the lone nuts in the country, it's like a country of lone gunmen who are nuts. . . ."

The serialization of it all on television, a soap opera of life, seemed to make it more difficult rather than easier for most Americans to deal with.

"At first we didn't know the president had been shot, then he had, then Brady was dead, then he was alive," said Father Donald Bilinski, curator of the Polish Roman Catholic Museum in Chicago. "It was all very difficult."

It was more difficult in some towns than others. In Dallas, still living with the John Kennedy stain, now living with a new gun bought there, a new gunman who went to school there, people were defensive. But they also mentioned their own fears.

"Violence has become a way of life in the U.S.," said Dr. David Whiting, a Dallas dermatologist. "It's almost a way of life here. I'm worried that I will get shot after having a minor traffic altercation."

Other places had their own special tie to Monday's shootings.

Thirty miles northwest of Santa Barbara, at the president's California home, the foreman of Reagan's Rancho del Cielo said he planned to call the president at George Washington University Hospital and tell him to "come back where you belong."

"Come back here. We love you. We're not going to shoot you," Lee Clearwater said he would tell the president.

In little Dixon, Ill., a place as typical of down-home Middle America as Main Street itself, the townsfolk cried and prayed. Dixon is Reagan's boyhood home, the town where he picked up the nickname "Dutch" and the reputation as a nervy teen-age lifeguard who plucked struggling swimmers out of the Rock River.

Mrs. Bernard J. Frazier, wife of Reagan's high school drama coach, said she had a premonition of the shooting and had written the president about it. "May God help him to recover and help bring us out of this terrible, terrible mess."

People gathered at a special prayer service in the tiny white-frame Second Baptist Church where the Rev. Donald Thomas urged America to "seek ways to end the violence that infects our life."

Still, for folks in Dixon the common emotion was that leaden feeling of deja vu -- of having been here before. "All I could think of was, 'No, not again. We need him,'" said Helen Lawton, a Reagan family friend and former neighbor.

In Atlanta, Dr. Ralph Abernathy was asked why he was trembling. "I'm trembling for my fellow man," he replied.

In Los Angeles, Rafer Johnson said he couldn't "come to grips" with this happening over and over again. "I just know that we can't continue along the lines we're stumbling now," the one-time Olympic decathlon star said.

In New York, on the other side of a complex country emotionally pulled asunder again, a Fifth Avenue sales clerk wisecracked: "Who shot him? His mother?"

In Washington, on the rain-slickened ceremonial street on which Reagan drove to his inaugural just 70 days earlier, hardly a motorist passed 1600 Pennsylvania Avenue without pausing in the early-morning hours following Monday's latest day of national trauma.

The drivers pulled over to the curb, peered through the iron fence at the darkened house over which an American flag flew at full staff -- and then drove on.