Watching the Valerie Plame scandal unfold, Daniel Ellsberg has dij` vu. In 1971, Ellsberg became the most famous leaker in American history with his release of the 7,000-page Pentagon Papers, a Defense Department study of the country's sordid involvement in Indochina. Besides revealing the lies and hypocrisy of American policy in a war its leaders knew was futile, Ellsberg's leak led Nixon to create the plumbers, the dirty tricks squad that broke into Ellsberg's psychiatrist's office looking for information to discredit him. Nixon's henchmen would use similar tactics against Democratic opponents, leading to the Watergate scandal and the president's downfall.

Today, Ellsberg says, America is in the early stages of a similar crisis. Once again, he says, the country is embroiled in a foreign war for murky reasons. Once again, he says, the White House has justified its policy with lies, and is smearing a whistle-blower who exposed those lies.

By now, the outlines of the new scandal are familiar. Last year, former ambassador to Gabon Joseph Wilson was dispatched to Niger to investigate claims that that country had sold uranium to Iraq. Even though Wilson determined that the allegation was groundless, George Bush used it to bolster his case for war in his State of the Union address. In July, months after the fall of Baghdad, Wilson went public in a New York Times Op-Ed. Shortly after, according to the Washington Post, two administration officials told columnist Robert Novak that Wilson's wife, Valerie Plame, was a CIA operative, blowing her cover. Wilson sees the leak as both an attempt to discredit him by suggesting he was only sent to Niger because of nepotism and as a warning from the White House that exposing administration mendacity can kill a career. As the scandal has grown hotter, conservatives have expressed bafflement and disbelief. But it's nothing new to Ellsberg.

A former Marine lieutenant and Harvard Ph.D., he worked on Vietnam policy in the Defense Department under Secretary Robert McNamara. In the preface to his 2002 book "Secrets: A Memoir of Vietnam and the Pentagon Papers," he writes of having watched America's leaders "maneuver the country into a full-scale war with no real promise of success." When he came forward, Nixon's plumbers took dangerous risks to undermine him, risks that can hardly be explained by rational political calculations. Ellsberg has seen firsthand that even among the savviest people, secrecy and vindictiveness can have a logic of their own.

At 72, Ellsberg despairs watching an administration whose malevolence he believes far exceeds that of his old foes on the Nixon team. His hope, he says, is that history continues its repetition, and that the White House's attempts to destroy its domestic enemies finally leads to its own destruction.

Do you see parallels between your experiences with the Pentagon Papers and what's happening to Joseph Wilson and his wife?

I see an almost identical pattern here. Really, I don't know of any analogy so close in the 30 years between now and then. This is not an everyday occurrence.

The origins of Watergate was an unauthorized disclosure by me that demonstrated a succession of presidential lies in a war that was still going on, lies that had lied us into war, exactly as in Iraq. In that case, that panicked the White House into fear that the leaker, in that case myself, would be imitated by others who would reveal information directly on Nixon, as I had not yet done -- the Pentagon Papers themselves ended in 1968, before Nixon came into office. He feared that I had more information on him that I would reveal.

Wilson of course did reveal his own work under Bush. His revelation gave the lie to Bush's own statement [about Iraq's nuclear program]. The White House undoubtedly fears that Wilson had more information that he could put out and above all that others would be led by seeing what a worthwhile effort this was, to tell the truth about the president's lies, and be moved to follow his example. To deter them, the White House has clearly been led to set up a project to discredit him and to punish him in ways that will deter others from following his example, and in the course of that they're willing to take criminal actions. It's an exact reproduction of the effort under [Nixon aides] Charles Colson, John Ehrlichman and Egil Krogh, Jr.

What I'm saying, then, is the plumbers are back.

Isn't there a difference, though? This administration is being accused of illegal leaking, and it may be that only two officials were involved. The plumbers were an organized group that committed crimes to staunch leaks.

The original plumbers operated by planning to leak. Their main operation was leaking. They went into my former psychoanalyst's office, they listened to me on warrantless wiretaps in order either to leak that information or to threaten me with leaks. In this case, they're sort of threatening other people by punishing Wilson. He said it was done to intimidate him. What does that mean? If they would not only break the law, but violate national security in order to punish him, it's a clear signal they'll do anything. There's no limit to what they'll put out.

What Valerie Plame was involved in was in the interests of the United States. She was involved in secret activity to find out about weapons proliferation. Let's assume she was trying to inhibit the spread of nuclear weapons. This was a necessary activity and one that the government has chosen to jeopardize by vindictively exposing.

Conservative defenders of the White House are saying that that narrative doesn't make sense -- they don't see how the administration would take such a huge risk for so little gain. Andrew Sullivan writes, "Like many others, I'm still baffled by the rationale."

Andrew Sullivan, like most people, is easily baffled when he needs to be. In this case it isn't that baffling when you know the context. Several of the [journalists] who have not revealed their sources have told Wilson of conversations they had [with administration leakers]. The word being used was "nepotism," that Wilson was sent to Niger on a kind of junket. There is a discrediting aspect that they're now pushing strongly. The implication of Novak's column is that the CIA was sending a biased person.

There may be an element here of Rove having a bad temper and getting specifically vindictive, but that's not an unusual trait at that level. People who get that job are tough guys, and there's a reason for it -- they really do need to keep these kinds of secrets, secrets of their lies and their crimes, because they pursue policies that have to be kept secret from the public.

We're now in an aggressive, costly war. The White House had to lie about those policies to make them viable, and when you lie you have to keep the lies secret, you have to intimidate people who might be inclined to tell the truth, all that goes together. Why do they do it? Wilson and I have no trouble knowing why they did it. They don't want people to act the way we do.

If the leaker really was someone high up in the administration, what do you think is going on in the White House now? Is the dynamic of a scandal like this something they can control?

I think we can predict from past experience what's going on in the White House. First, there's the realization that they have one of these daily or weekly crises. There may be a growing sense -- but here I may be a little ahead of them -- that this one has real possibilities for bringing them down. Part of that is because the administration has said that the president knows of no one in the White House being involved. That is almost surely a lie, and it's a lie that is now entangled in a legal process. The FBI is going to be asking who knew what when. [White House spokesman Scott] McClellan says the president knows that Rove has no involvement. That statement is going to be declared inoperative. At the very least, Rove was clearly involved in calling people up and saying Valerie Plame is fair game.

They have already made statements they are going to have to reverse. It is not going to end up that there was no White House involvement. One leak, even of an undercover agent, is not going to look like an impeachable offense, but the lies and obstruction of justice going on now, that stuff is going to come out, and that stuff is going to look impeachable. I can see just how this is going to go down now that there's a legal process as there was in Watergate.

Of course, we wouldn't want to impeach Bush. Cheney is Bush's impeachment insurance, just as Spiro Agnew was Nixon's impeachment insurance. We need to get them all out of there.

But didn't Nixon's downfall depend on some outraged Republicans turning against him? That seems less likely now -- the parties are so much more polarized and zealously partisan.

Once you get people being questioned by the FBI and going before a grand jury, someone is likely to be unwilling to commit perjury. Under Nixon, it reached that point because I was on trial and there was a legal obligation to pass on certain information to my judge. Nixon was withholding the information about breaking into my doctor's office from my trial. There you had a case where Republicans in the Justice Department finally went to the president and said, "You've got to send the information." They were implying they would resign because they didn't want to be caught in obstruction of justice.

There's no exact counterpart here, but there's a real chance someone in the White House will crack on this. Maybe even for conscientious reasons.

The other part is outside the White House; there's the call for a special prosecutor. The administration is trying to hold the Republican line very closely on this, but if you look at the New York Times, it says a Republican with close ties to administration says the White House was monitoring five Republicans in Congress, all of whom have an independent streak. Putting pressure on them -- to tell the truth, to follow their conscience, to break ranks -- would be very worthwhile. This is the time for Democrats and Republicans to be telling those guys, "Do your duty to the country. Don't follow White House discipline on this."

Republicans are trying to paint Wilson as some kind of rabid leftist. That characterization is absurd, but watching him, it looks like he might have been radicalized by this experience. How does going through something like this, and seeing your government do things you never would have imagined, change the way you view the world?

Of course, to call Wilson a rabid leftist is simply ridiculous. His first ambassadorship was under Bush I. He was praised by Bush for his performance [working at the embassy] in Iraq before the first Gulf War.

As for me, I did change in various ways, in particular about my trust in presidents to tell us the truth or to judge our national interest or values reliably. I converted to a belief that the Constitution had it right the first time to take the power of war and peace out of the White House and put it into the hands of Congress so we didn't have an elected king.

I was a cold warrior. I never ceased to be anticommunist. I found the communist system abhorrent. But I became aware that so much of our policy was not any more prudent or productive in terms of fighting communism than an attack on Iraq is a justifiable aspect of our war on terror.

Like you, Wilson has a formidable political machine lined up against him. Do you have any advice for him?

Everything I've seen him do so far has been admirable and exemplary. He certainly has a picture now about what they're prepared to do against him -- he doesn't need to have me warn him.

My advice is not to Wilson but to other people. The purpose of going after Wilson, as in going after me, was to intimidate him and to intimidate other people. I'm totally confident now that he can't be intimidated. He isn't intimidated any more, if I may say, than I was.

What I would really urge is for other people to thwart the White House's hope that they would be intimidated. I want to encourage people to tell the truth, but not by misleading them that it's without risk. My advice to these other people is to consider telling important truths about government lies that are dangerous to this country, consider telling those truths even though you know that they'll go after you personally and professionally. They'll try to destroy your career. They might even try to put you in jail.

CIA analysts said they were appalled that the president used such bogus information [to justify the Iraq war]. My advice to them then and now is that, when they're appalled by misinformation by the president, they should consider risking their careers, risking even going to prison, to correct such bogus information by telling Congress, putting it in the press with documents, and/or coming out publicly.

Do you agree with John Dean that this administration is even more vicious than Nixon's? If so, does that mean they'll be harder to fight?

In terms of the administration, this gang is really different in degree. All administrations lie and others have gotten us into wrongful wars. They haven't invented that stuff. But in terms of their antipathy to democracy, they're unusual.

But what about the rest of the system? In Watergate, the system did work and it worked pretty well. The day my trial was dismissed, Nixon said, "What in the name of God have we come to?" What we'd come back to was a democratic republic, not a monarchy.

Are we seeing that yet? No, but that's not new either. The system really failed on Irangate, Contragate. I didn't believe Reagan and Bush could get away without being impeached, and they did. And they could get away this time. They can cover up anything with enough help from the Congress, enough help from the media and enough apathy from the public.

But if guys like Sens. John McCain [R-Ariz.] and Chuck Hagel [R-Neb.], if they want to hold hearings, we could move ahead. In that case, this leak could turn out to be very good. It could bring down a terrible administration. If Rove made that leak, it would be the best thing he ever did for the country, given that he got caught.