It is testimony to these jittery times that an altogether mediocre bomb scare involving two pseudorevolutionary mopes rattled Atlanta like nothing since Sherman’s march. Although government sources quickly retracted the notion that Starr and McCranie planned to disrupt the Summer Games, the 1996 Olympics are a multibillion-dollar extravaganza that will attract 2 million spectators, thousands of athletes and 40 heads of state–a fat target. Think of Munich, Oklahoma City or the World Trade Center: an attack can come in many forms and for as many reasons as the paranoid mind can conceive. “The threat assessment is close to an all-time high,” said Brian Jenkins, a counterterrorism expert for Kroll Associates, a New York-based security-consulting firm. Jenkins’s counterparts in government, according to NEWSWEEK sources, are currently debating whether foreign or domestic terrorism poses the greater risk.

It doesn’t matter. The Atlanta Olympics are a security nightmare for many reasons, not the least of which is the fact that this year’s Games will be dispersed over an area stretching all the way from Savannah to eastern Tennessee. There are also two disturbing background trends. The first is that all kinds of groups–American right-wingers, religious sects, breakaway ethnic groups and, as always, Arab fundamentalists – seem to be nursing powerful grudges. The second is the spread of the once unobtainable means of destruction–bombs, chemical and biological agents, even nuclear weapons. The World Trade Center and Oklahoma City bombings show that almost anyone can make a fertilizer bomb; the Tokyo subway disaster shows that any good chemist can make nerve gas. The 1972 tragedy in Munich, when Arab terrorists killed 11 members of Israel’s Olympic team, was the work of trained commandos who planned their strike for months. But a dozen pipe bombs–the number Starr and McCranie allegedly had in mind–could cause an equal horror.

The rise of the U.S. militia movement now confronts federal authorities with a plausible risk of terrorism from within. Worse, from the FBI’s point of view, the American ultraright has widely adopted the concept of “leaderless resistance,” which means its adherents organize themselves in tiny cells that are exceedingly difficult to detect or infiltrate. And there are numerous incidences of recent militia activity that give one pause. Among them:

In April 1993 Thomas Lavy, 54, was stopped by Canadian customs officials with four guns, 20,000 rounds of ammunition, $89,000 in cash, a supply of neo-Nazi literature and a plastic bag containing a white powder Lavy identified as ricin. The bag was confiscated and Lavy went home to Arkansas. Months later, Canadian authorities got the powder analyzed and confirmed that it was ricin–one of the most powerful toxins known to science and a closely controlled chemical weapon. According to the FBI, the amount in Lavy’s bag could have killed 32,000 people.

Still, no alarm bells rang until mid-1995, when the FBI belatedly began to investigate. Lavy was arrested at his cabin near Onia, Ark., and charged with carrying a biological agent with intent to use it as a weapon. Held without bail in Little Rock, he reportedly hanged himself in his cell just before Christmas. Where did he get the ricin, and what did he plan to do with it? Authorities don’t know – though last year, in what may be an unrelated incident, two members of a Minnesota “patriot” group were convicted of planning to use ricin to kill federal law-enforcement officials.

In Lancaster, Ohio, patriot Larry Harris, 44, was arrested a year ago for allegedly buying three vials of freeze-dried bubonic-plague bacteria through the mail. Police reportedly found hand-grenade triggers, detonating fuses and homemade explosives in his home. His lawyer says Harris was researching a book on germ warfare. If investigators have another explanation, it may come out at his trial on May 28.

In Muskogee, Okla., last week, two men and a woman were convicted of plotting to use fertilizer bombs to attack gay bars, abortion clinics, government offices and two groups that track right-wing hate groups, the Anti-Defamation League of B’nai Brith and the Southern Poverty Law Center in Montgomery, Ala. Though an informer stopped the plan, the police found fertilizer-bomb materials at the home of lead defendant Willie (Ray) Lampley of Vernon, Okla.

With the Olympics only three months away, federal authorities are building what may well be the biggest counterterrorist screen in history. The force includes the FBI, the CIA, the Secret Service, local and state police and U.S. military units. A training exercise two weeks ago forced field commanders to react to a nerve-gas attack and a plane hijacking simultaneously; another test simulated the detonation of a small nuclear device. So while last week’s bomb scare involved “two yahoos, Gomer and Goober,” as a Justice Department official put it, the Feds are preparing for the worst. Here’s hoping they don’t find it.