In the past, a list like the one found in December at the high school in the small, west Idaho town of Parma might have been viewed as a not-very-amusing, even disturbed joke. It consisted of the names of 30 boys and 30 girls, fully 20 percent of the student body, many of them athletes and minorities, under the heading: "People to Kill, 12/17/99."

But school officials and town police--mindful of the violence that shattered the peace in schools, churches and workplaces from Alabama to Washington state last year--were taking no chances when a student turned in the list she said she found on the floor after health class Dec. 9. They sprang into action in the final days before the holiday break, hauling in portable metal detectors to scan every entering student, dispatching practically the entire police squad of the town of 1,800 to patrol the school hallways and enforcing a new rule: Students are not allowed to carry any sort of book bag or gym bag to school.

"It's hard to say, but we probably wouldn't have treated it the same way years ago. We would probably have written it off as somebody's stupid idea of a cruel joke," said Clif Lauritzen, acting police chief of the farming town 40 miles west of Boise. "But can we afford not to take it seriously? I don't think so."

Fortunately, nothing happened at Parma High School, although police continue to search for the author of the list. But the episode, which briefly made national headlines, highlighted a fundamental change in the national psyche that has evolved over the past year: No longer do Americans automatically dismiss the notion of someone opening fire in their office or schoolyard or church sanctuary with the bromide, "It could never happen here."

Now, there is an acute public awareness that violent tragedy can occur anywhere, as easily in Fort Gibson, Okla., where a 13-year-old middle-school student opened fire with a semiautomatic handgun Dec. 6, wounding four students, as in Fort Worth, where a gunman walked into a church prayer rally for teenagers Sept. 15 and fatally shot seven worshipers before turning the gun on himself.

The bloodshed continued right up until the year's end. On Thursday, an employee at a Tampa hotel packed with holiday football fans opened fire, killing four co-workers and wounding three others. The employee, Silvio Izquierdo-Leyva, 36, a housekeeper at the Radisson Bay Harbor Inn, killed a fifth person as he attempted a carjacking to escape.

Police captured Izquierdo-Leyva but as yet have determined no motive for the shootings.

Something vital shifted during the turbulent months of 1999, despite statistics showing that violent crime is down overall.

In interviews with crime analysts, university professors, police officers and citizens, it is clear that while such mass public shootings can still stun, they no longer surprise.

Media-fueled images have been seared into the public consciousness forever: panicked students streaming out of Columbine High School in Littleton, Colo., on an April afternoon, fleeing a scene where 15 people, including the two teenage gunmen, lay dead or dying; or a line of small children, most too young to realize fully the danger they were in, exiting hand-in-hand from a Los Angeles Jewish community center in August after a white supremacist shot and wounded five people there. As these tragedies have dominated the news, involving more cities and towns across America, public comfort levels have plummeted.

"I guess you could say we have had a kind of wake-up call around here," Lauritzen said last week. "Sometimes people go through life fat, dumb and happy, thinking nothing can ever happen here. Well, it's happening everywhere else, why not here?"

Although indications are that few people actually fear for their own personal safety when they go to church or work or school--and the knowledge of these shootings apparently has not curtailed public outings--more people now seem to consider the possibilities of getting caught in such gunfire.

"I always thought this area was so nice and quiet and safe, but it's not safe, and no place is safe anymore. It's something I think about all the time," said Aeta Hwang, who runs a dry-cleaning business in the Birmingham suburb of Pelham, Ala., where a man opened fire at two companies one morning in early August, killing three people--marking the nation's second workplace shooting in a week's time. On July 29, in the Atlanta area, disturbed stock trader Mark O. Barton had killed nine people and wounded 13 others at two day-trading firms after slaying his wife and two children; he committed suicide that night as police closed in.

Alan Lipman, a professor of clinical and criminal psychology at Georgetown University, said that while there is "a slight increase in workplace violence, there is not an increase in agoraphobia," or fear of public places.

"There is no reason to believe in terms of large numbers that this society as a whole is beginning to fear going out," he said recently. "I don't think it's denial. There's still no question that most of our schools are safe, most of our workplaces are safe, and while we should become more sensitized to the possibility of violence happening, it is critically important not to go overboard."

Since the fall of 1997, when a 16-year-old boy in Pearl, Miss., killed his mother, then went to school and fatally shot two students and wounded seven others, there have been nine school shootings across the country, according to the Associated Press and other news reports.

Three occurred this year--the case in Fort Gibson, Okla.; in Conyers, Ga., where a 15-year-old boy in May wounded six students with a .357 Magnum and a rifle; and in Littleton, Colo., the most unforgettable and deadly case of all.

"Columbine was different," Lipman said about the April 20 tragedy where teenagers Dylan Klebold and Eric Harris killed 12 students and one teacher, effectively holding the school hostage before killing themselves. "The scope and degree of violence made an unusual and specific mark on the nation."

Jack Levin, director of the Brudnick Center on Violence at Northeastern University in Boston, said the mass shootings this year by adults reflected "more apocalyptic thinkers who are translating their doom-and-gloom visions into murder."

He cited Benjamin Smith, a member of a hate group, the World Church of the Creator, who in July went on a spree near Chicago, killing a black former college basketball coach and a Korean graduate student, and injuring six Orthodox Jews. Levin also included in that category Buford O. Furrow Jr., charged in the shootings at the Los Angeles Jewish community center and with the slaying of a Filipino mail carrier later the same day, and Larry Gene Ashbrook, who went on the rampage in the Fort Worth church.

Levin fears Americans are not learning very much from these episodes. "I hate to say it, but we look at short-term, expedient solutions," he said. "We make our schools into armed camps by stationing metal detectors everywhere. It makes us feel safe, even if we are not."

Tom Rosenstiel, director of the Project for Excellence in Journalism, argues that the mass media, with its penchant for what he calls "the big-story syndrome," must seriously review its role in the events of the past year.

"To some extent, there's a limit to what the press can worry about," he said. "If a deranged person sees something in the news, you can't hold the journalist responsible for this crime. We can ask, is the coverage glorifying the killer? Is it making a more famous person than he or she should be, given the significance of the crime?"

Competition between media outlets also often comes into play, he said. What happened in San Antonio in November may illustrate that point.

On Nov. 9, news flashes on two San Antonio television stations and one radio station reported that there had been yet another school shooting, this time at Coker Elementary School.

One report said that as many as 14 students had been injured by shattered glass, and at least 60 parents reportedly heard the broadcasts. Some panicked, rushing to the school to find their children.

It turned out, however, that the reports were false. What did happen, said San Antonio police spokeswoman Sandy Gutierrez, was that a school employee's truck was shot at, in a case of suspected road rage, as he was driving to work that morning. When he arrived at Coker, he made the call to report the incident to police from a school telephone, which led to the confusion. The San Antonio Express-News reported the next day that the shooting report was taken from inaccurate emergency radio transmissions.

"The incident occurred miles from the school, and at no time were teachers or students in any danger," Gutierrez said.

News director Jim Boyle at KSAT television in San Antonio, which is owned by The Washington Post Co., accepted blame for his station's actions. "Obviously, we made a mistake," he said. "We had believed we had confirmed the story, but we were wrong."

Nick Simonette, news director at KENS television station in San Antonio, said he had no comment.

But Michael Main, managing editor at San Antonio radio station WOAI, had plenty to say about the incident. His station held off reporting the alleged shooting, citing the confusion often surrounding 911 calls.

"Certainly the media overreaction was prompted by Columbine," he said, "but also a lot by the intense media market, trying to be first with the story. Surely, no one wants to report a shooting at an elementary school. Unfortunately, everybody ended up having to report a story they wouldn't have reported at all. We had to tell people there was not a shooting, which was, well, bizarre."

Staff researcher Lynn Davis contributed to this report.

CAPTION: A police officer searches Parma, Idaho, high school grounds with a dog in December, after a "hit list" of 60 students was found on a classroom floor.