The Bush Administration, while publicly advocating diplomacy in order to stop Iran from pursuing a nuclear weapon, has increased clandestine activities inside Iran and intensified planning for a possible major air attack. Current and former American military and intelligence officials said that Air Force planning groups are drawing up lists of targets, and teams of American combat troops have been ordered into Iran, under cover, to collect targeting data and to establish contact with anti-government ethnic-minority groups. The officials say that President Bush is determined to deny the Iranian regime the opportunity to begin a pilot program, planned for this spring, to enrich uranium. (my emphasis)

American and European intelligence agencies, and the International Atomic Energy Agency (I.A.E.A.), agree that Iran is intent on developing the capability to produce nuclear weapons. But there are widely differing estimates of how long that will take, and whether diplomacy, sanctions, or military action is the best way to prevent it. Iran insists that its research is for peaceful use only, in keeping with the Nuclear Non-Proliferation Treaty, and that it will not be delayed or deterred. (my emphasis)

There is a growing conviction among members of the United States military, and in the international community, that President Bush's ultimate goal in the nuclear confrontation with Iran is regime change. Iran's President, Mahmoud Ahmadinejad, has challenged the reality of the Holocaust and said that Israel must be "wiped off the map." Bush and others in the White House view him as a potential Adolf Hitler, a former senior intelligence official said. "That's the name they're using. They say, 'Will Iran get a strategic weapon and threaten another world war?' "

A government consultant with close ties to the civilian leadership in the Pentagon said that Bush was "absolutely convinced that Iran is going to get the bomb" if it is not stopped. He said that the President believes that he must do "what no Democrat or Republican, if elected in the future, would have the courage to do," and "that saving Iran is going to be his legacy."

One former defense official, who still deals with sensitive issues for the Bush Administration, told me that the military planning was premised on a belief that "a sustained bombing campaign in Iran will humiliate the religious leadership and lead the public to rise up and overthrow the government." He added, "I was shocked when I heard it, and asked myself, 'What are they smoking?' "

In recent weeks, the President has quietly initiated a series of talks on plans for Iran with a few key senators and members of Congress, including at least one Democrat. [Anyone want to bet on Joe Lieberman?] A senior member of the House Appropriations Committee, who did not take part in the meetings but has discussed their content with his colleagues, told me that there had been "no formal briefings," because "they're reluctant to brief the minority. They're doing the Senate, somewhat selectively."

The House member said that no one in the meetings "is really objecting" to the talk of war. "The people they’re briefing are the same ones who led the charge on Iraq. At most, questions are raised: How are you going to hit all the sites at once? How are you going to get deep enough?" (Iran is building facilities underground.) "There’s no pressure from Congress" not to take military action, the House member added. "The only political pressure is from the guys who want to do it." Speaking of President Bush, the House member said, "The most worrisome thing is that this guy has a messianic vision." (my emphasis)

But those who are familiar with the Soviet bunker [on which Iranian facilities are said to be modeled], according to the former senior intelligence official, "say 'No way.' You’ve got to know what’s underneath—to know which ventilator feeds people, or diesel generators, or which are false. And there’s a lot that we don't know." The lack of reliable intelligence leaves military planners, given the goal of totally destroying the sites, little choice but to consider the use of tactical nuclear weapons. "Every other option, in the view of the nuclear weaponeers, would leave a gap," the former senior intelligence official said. " 'Decisive' is the key word of the Air Force’s planning. It's a tough decision. But we made it in Japan."

He went on, "Nuclear planners go through extensive training and learn the technical details of damage and fallout — we're talking about mushroom clouds, radiation, mass casualties, and contamination over years. This is not an underground nuclear test, where all you see is the earth raised a little bit. These politicians don't have a clue, and whenever anybody tries to get it out" — remove the nuclear option —"they’re shouted down." (my emphasis)

The attention given to the nuclear option has created serious misgivings inside the offices of the Joint Chiefs of Staff, he added, and some officers have talked about resigning. Late this winter, the Joint Chiefs of Staff sought to remove the nuclear option from the evolving war plans for Iran—without success, the former intelligence official said. "The White House said, 'Why are you challenging this? The option came from you.' "

The Pentagon adviser on the war on terror confirmed that some in the Administration were looking seriously at this option, which he linked to a resurgence of interest in tactical nuclear weapons among Pentagon civilians and in policy circles. He called it "a juggernaut that has to be stopped." He also confirmed that some senior officers and officials were considering resigning over the issue. "There are very strong sentiments within the military against brandishing nuclear weapons against other countries," the adviser told me. "This goes to high levels." The matter may soon reach a decisive point, he said, because the Joint Chiefs had agreed to give President Bush a formal recommendation stating that they are strongly opposed to considering the nuclear option for Iran. "The internal debate on this has hardened in recent weeks," the adviser said. "And, if senior Pentagon officers express their opposition to the use of offensive nuclear weapons, then it will never happen."

The adviser added, however, that the idea of using tactical nuclear weapons in such situations has gained support from the Defense Science Board, an advisory panel whose members are selected by Secretary of Defense Donald Rumsfeld. "They're telling the Pentagon that we can build the B61 with more blast and less radiation," he said.

The Pentagon adviser said that, in the event of an attack, the Air Force intended to strike many hundreds of targets in Iran but that "ninety-nine per cent of them have nothing to do with proliferation. There are people who believe it’s the way to operate"—that the Administration can achieve its policy goals in Iran with a bombing campaign, an idea that has been supported by neoconservatives.

The Pentagon adviser on the war on terror said that "allowing Iran to have the bomb is not on the table. We cannot have nukes being sent downstream to a terror network. It's just too dangerous." He added, "The whole internal debate is on which way to go" — in terms of stopping the Iranian program. It is possible, the adviser said, that Iran will unilaterally renounce its nuclear plans - and forestall the American action. "God may smile on us, but I don't think so. The bottom line is that Iran cannot become a nuclear-weapons state. The problem is that the Iranians realize that only by becoming a nuclear state can they defend themselves against the U.S. Something bad is going to happen." (my emphasis)

In recent months, the Pakistani government has given the U.S. new access to A. Q. Khan, the so-called father of the Pakistani atomic bomb. Khan, who is now living under house arrest in Islamabad, is accused of setting up a black market in nuclear materials; he made at least one clandestine visit to Tehran in the late nineteen-eighties. In the most recent interrogations, Khan has provided information on Iran’s weapons design and its time line for building a bomb. "The picture is of 'unquestionable danger,' " the former senior intelligence official said. (The Pentagon adviser also confirmed that Khan has been "singing like a canary.") The concern, the former senior official said, is that "Khan has credibility problems. He is suggestible, and he's telling the neoconservatives what they want to hear" — or what might be useful to Pakistan’s President, Pervez Musharraf, who is under pressure to assist Washington in the war on terror.

"I think Khan’s leading us on," the former intelligence official said. "I don’t know anybody who says, 'Here’s the smoking gun.' But lights are beginning to blink. He's feeding us information on the time line, and targeting information is coming in from our own sources — sensors and the covert teams. The C.I.A., which was so burned by Iraqi W.M.D., is going to the Pentagon and the Vice-President's office saying, 'It's all new stuff.' People in the Administration are saying, 'We've got enough.' " (my emphasis)

Last year, the Bush Administration briefed I.A.E.A. officials on what it said was new and alarming information about Iran’s weapons program which had been retrieved from an Iranian’s laptop. The new data included more than a thousand pages of technical drawings of weapons systems. The Washington Post reported that there were also designs for a small facility that could be used in the uranium-enrichment process. Leaks about the laptop became the focal point of stories in the Times and elsewhere. The stories were generally careful to note that the materials could have been fabricated, but also quoted senior American officials as saying that they appeared to be legitimate. The headline in the Times’ account read, “RELYING ON COMPUTER, U.S. SEEKS TO PROVE IRAN’S NUCLEAR AIMS.”

I was told in interviews with American and European intelligence officials, however, that the laptop was more suspect and less revelatory than it had been depicted. The Iranian who owned the laptop had initially been recruited by German and American intelligence operatives, working together. The Americans eventually lost interest in him. The Germans kept on, but the Iranian was seized by the Iranian counter-intelligence force. It is not known where he is today. Some family members managed to leave Iran with his laptop and handed it over at a U.S. embassy, apparently in Europe. It was a classic “walk-in.”

A European intelligence official said, “There was some hesitation on our side” about what the materials really proved, “and we are still not convinced.” The drawings were not meticulous, as newspaper accounts suggested, “but had the character of sketches,” the European official said. “It was not a slam-dunk smoking gun.”

The central question—whether Iran will be able to proceed with its plans to enrich uranium—is now before the United Nations, with the Russians and the Chinese reluctant to impose sanctions on Tehran. A discouraged former I.A.E.A. official told me in late March that, at this point, "there’s nothing the Iranians could do that would result in a positive outcome. American diplomacy does not allow for it. Even if they announce a stoppage of enrichment, nobody will believe them. It’s a dead end."

Another diplomat in Vienna asked me, “Why would the West take the risk of going to war against that kind of target without giving it to the I.A.E.A. to verify? We’re low-cost, and we can create a program that will force Iran to put its cards on the table.” A Western Ambassador in Vienna expressed similar distress at the White House’s dismissal of the I.A.E.A. He said, “If you don’t believe that the I.A.E.A. can establish an inspection system - if you don’t trust them - you can only bomb.” (my emphasis)

A key ally with an important voice in the debate is Israel, whose leadership has warned for years that it viewed any attempt by Iran to begin enriching uranium as a point of no return. I was told by several officials that the White House’s interest in preventing an Israeli attack on a Muslim country, which would provoke a backlash across the region, was a factor in its decision to begin the current operational planning. In a speech in Cleveland on March 20th, President Bush depicted Ahmadinejad’s hostility toward Israel as a “serious threat. It’s a threat to world peace.” He added, “I made it clear, I’ll make it clear again, that we will use military might to protect our ally Israel.”