Whistleblowing, that often lonely, conscience-driven act of calling the boss to book, has become enough of an institution that, conferences now are held on the subject.

Just such a conference has been going on here this weekend, involving some of the biggest names in recent whistleblowing - Ellsberg, Stockwell, Snepp, Conrad, Mancuso and others of lesser renown.

This second annual session was staged by the Institute for Policy Studies, which attracted several hundred government and congressional workers to hear case histories and be encouraged to blow their whistles.

It takes some hours of listening to these vignettes and hearing the stories of punishment and retaliation to catch a common strain that runs through them all.

Your average whitleblower turns out not to be the ranting kook of popular perception. More often, he is a frustrated agency employe who goes public because he believes his superiors are suppressing the truth.

And, just as often, he suffers prosecution, relegation to the bureaucratic deep-freeze or outright firing for having gone outside the agency channels that did not respond to him in the first place.

If there was any central tone running through this conference, it was underlined by Morton Halpern, the former national security aide whose telephone was illegally tapped by a Nixon administration that thought he was a "leak."

Halpern warned the whistleblowers that their peril is likely to be greater under the Carter administration, which he said "has succeeded where Richard Nixon failed."

Halperin and others said the Carter White House is moving directly against whistleblowers and dissenters by a series of actions, including support of a criminal code revision, designed to make disclosure of government information a crime or at least a breach of nebulous contract.

"Any last remaining hope that anybody had that this administration would be different is gone," he said. "If the enemy is not us, he at least is always the man in the White House."

Sen. James Abourezk (D-S.D.), sponsor of a strong bill to protect the due process rights of whistleblowers, used even tougher language.

"This administration has cynically ignored its campaign promises in this area," Abourezk said. "It ignores the evils of the past. It refuses to prevent a repetition of such evils."

"I can only conclude that this administration, without a doubt, is deliberately pursuing a Nixonesque policy of retaliation, intimidation and suppression of whistleblowers, their revelations and their complaints," he said.

Moreover, he added, "In agency after agency the same thugs who terrorized government workers and betrayed the public trust under Nixon and Ford are doing business as usual."

He said the Civil Service Commission "has run a whistleblowers' graveyard over there. No honest civil servant worthy of the name would neither trust or seek out the commission in the interests of fair play and justice."

Abourezk said that more than fair play is involved, citing the troubles of Frank Snepp and John Stockwell, the former CIA men who wrote books critical of agency operations in Vietnam and Angola.

"Snepp and Stockwell did not sign away their First Amendment rights," he said. "The agency is not the master, nor the employe its slave."

Tht two, among the more celebrated whistleblowers of the year, were on hand together Friday evening as panel members to discuss their problems.

Snepp said he agrees generally that "the government is tightening the screws on the intelligence community," but that potential whistleblowers at the CIA have a responsibility to "stand up and face the legal consequences of their actions as well."

Like Snepp, Stockwell professed strong belief in the intelligence-gathering function of the CIA. But he said that bungled covert operations abroad, such as the one in Angola that he wrote about, do the United States More harm than good.