Wanted: a few good whistle-blowers.

That is the message the American Civil Liberties Union is sending to federal workers with an advertisement today in the independent weekly newspaper Federal Times.

Headlined "A Call to All Persons to Ensure That Congress Is Kept Fully Informed About What the Administration Is Doing in the Persian Gulf," the ad solicits government employees to step forward if they have evidence that Congress is being misled.

Those with "knowledge that Congress has been misled by government officials about administration actions or plans in the Persian Gulf have the legal right and a political responsibility to act to ensure that Congress has the information it needs to perform its Constitutional functions," the ad says.

Prospective whistle-blowers are advised that government employees who report classified information regarding government misconduct to Congress are breaking no law, but that "there is a practical risk" of disciplinary action. And while it "may also be appropriate to give information regarding unlawful conduct to the press," the ad cautions, that could lead to criminal prosecution.

It concludes with an ACLU number -- not toll-free -- for those who have information and want legal advice on "how to set the record straight."

Morton Halperin, who heads the ACLU's Washington office, said the group's proactive approach to whistle-blowing was inspired when "we began to think about how we had gotten involved in previous crises of this kind -- like Vietnam and Iran-contra -- and realized what happened was, there was testimony before congressional committees which was misleading."

While "we don't know that there's going to be deception . . . evidence of the past certainly suggests that could happen," he said. "We think that calling people's attention to this problem could well trigger people coming forward."

Halperin, a former National Security Council aide whose home telephone was wiretapped during the Nixon administration, said the group also will warn would-be whistle-blowers that "even though legally you're protected, in fact you're going to be harassed. We're not going to in any way downplay the consequences of your doing it. We're also going to talk about what we think of as their moral obligation to do it."

The ACLU is holding a news conference today to announce its offensive and is considering local radio ads, Halperin said. Asked how far the ACLU plans to take its advertising, or if it might target direct mailings to key officials, Halperin laughed. "We don't have those names," he said. "If we did, we might do that."