The story of the "sting" has been portrayed as the greatest scandal since Watergate. It is not. But from the moment it began to dominate the news Saturday night, this tale of old-fashioned political corruption has shaken the capital and raised more troubling ethical questions than anything in years.

At the heart of the concern stands the role of the FBI.

In this most suspicious if not cynical city, old doubts and fears are being stirred. They go beyond even the possible entrapment aspects of this case. As one former high government official said yesterday, "It triggers a certain paranoia about the FBI in you. Turn loose the FBI for a year and a half with a million bucks in cash and they can get anybody."

What we have at this point are allegations -- played for maximum publicity -- of members of Congress being bribed during an undercover FBI operation. No one has been charged with a crime, no one has been brought before a grand jury and few of the many questions surrounding this government-spying-on-the-government episode have been answered.

For instance:

It is being said, from those "reliable" sources in which Washington deals so extensively, that the FBI could have gone on for much more time and caught many more figures in its net. Why didn't it?

Then it is said the Justice Department is investigating leaks to the press that supposedly forced the FBI to halt its investigation. But some in the media obviously had been primed well in advance of the denouement Saturday night, just as news organizations were privy to the story for weeks, if not months, before.

An NBC van, for example, pulled up in front of the Georgetown home of Sen. Harrison A. Williams Jr. (D-N.J.) Saturday morning. Hours later, network cameras from inside that van were rolling as FBI agents knocked on the senator's door to inform him of the investigation. Other NBC correspondents were deployed in advance to homes of the other members of Congress named.

TV coverage of the news that night and Sunday newspaper accounts showed that elements of the media were prepared to go with the story before it broke officially.

It was, of course, an extraordinary story. No reporter or news organization would fail to go after it with full energy. What are being raised now, though, are suspicions about how the individuals targeted for the investigation were selected.

It has been reported that FBI agents began approaching the politicians after tips from an informer.

But Sen. Larry Pressler (R-S.D.), whose political reputation has been enhanced after government sources said he rejected cash donations as illegal, says he stumbled into the setup "through a social friend."

Another former high government official, who at one time had major responsibility over the FBI, expressed his concern over the case this way:

"We used to get cases in which allegations had been made against someone. If after investigation we thought there was probable cause to proceed against that person, often we'd wire him [install a tap on his telephone, home, or place of business.] But this seems to have a different quality to it.

"How were these guys targeted in the first place? It seems at random without any particular pattern. Just throwing out a net and seeing what you set up to catch. Now I say 'seems' because we don't know much about any of the motivations or methods in this case."

The civil liberties view was put by John Shattuck, who heads the Washington office of the American Civil Liberties Union.

"This raises very serious questions about the scope of FBI undercover operations," he says. "It appears that government agents have been in the field for well over a year, building a case from nothing, a case that does not appear to be focused on anyone. It suggests a kind of runaway operation. It also suggests the need of much more judicial controls. Among the other questions it raises is the whole area of prejudicial publicity."

What you also hear are fears about a set of other questions: were other politicans involved? If so, why didn't the FBI proceed with the investigation? And then why was the trap sprung so suddenly?

In past years, an FBI investigation of political corruption just as likely would have wound up with the names of suspects kept in J. Edgar Hoover's private file -- for use when, and if, needed. The belief that Hoover was compiling secret dossiers on public officials was part of the power he wielded so long. And, in part, it stood at the center of the abuses that stained the FBI's reputation and diminished its standing.

Much of the concern now being voiced here stems from remembrance of that era.

But this latest case has broader implications. At a moment when political leaders and institutions are attempting to regain public faith in their integrity and ability, these allegations come as a major blow. They also raise even greater challenges -- both from the political leadership in Congress and in the press.

Whatever wrongdoing may have been committed, everyone involved is entitled to absolutely fair treatment and the presumption of innocence. The danger is that the present climate of such massive coverage of allegations breeds the possibility of lynch justice.

Beyond that, this case comes down to a fundamental. The charges being raised have nothing to do with private affairs. They all involve the public business. And even an absence of criminal charges does not negate the clear responsibility of those who conduct the public's business.

They have an ethical responsibility, if not a legal one, to address all these questions directly -- and, if necessary, to set their own houses in order.