We may never know exactly when President Bush made up his mind to invade Iraq--some analysts say the die was cast as early as November 2001; others claim it was not until October 2002--but whatever the case, it is beyond dispute that planning for the invasion was well advanced in July 2002, when British intelligence officials visited Washington and issued what has come to be known as the Downing Street memo, informing Prime Minister Tony Blair that war was nearly inevitable.

What these officials undoubtedly discovered--as was being reported in certain newspapers at the time--was that senior officers of the US Central Command (CENTCOM) in Tampa, Florida, had already been developing detailed scenarios for an invasion of Iraq and that Defense Secretary Donald Rumsfeld had been deeply involved in these preparations. On July 5, 2002, for example, the New York Times revealed that "an American military planning document calls for air, land, and sea-based forces to attack Iraq from three directions--the north, south, and west." Further details of this document and other blueprints for war appeared in the Washington Post and the Wall Street Journal. At the same time, moreover, the Pentagon reportedly stepped up its aerial and electronic surveillance of military forces in Iraq.

This record is worth revisiting because of the many parallels to the current situation. Just as Bush gave ambiguous signals about his intentions regarding Iraq in 2002--denying that a decision had been made to invade but never ruling it out--so, today, he is giving similar signals with respect to Iran. "This notion that the United States is getting ready to attack Iran is simply ridiculous," Bush declared in Belgium on February 22. He then added: "Having said that, all options are on the table." And, just as Bush's 2002 denials of an intent to invade Iraq were accompanied by intense preparations for just such an outcome, so, today, one can detect similar preparations for an attack on Iran.

Just what form such an attack might take has probably not yet been decided. Just as he considered several plans for an invasion of Iraq before settling on the plan described in the Times, Rumsfeld is no doubt considering a variety of options for action against Iran. These could range from a burst of air and missile attacks to a proxy war involving Iranian opposition militias or a full-scale US invasion. All have obvious advantages and disadvantages. An air and missile attack would undoubtedly destroy some key nuclear centers but could leave some hidden facilities intact; it would also leave the hated clerical regime in place. The use of proxy forces could also fail in this regard. An invasion might solve these problems but would place almost intolerable demands on the deeply over-stretched US Army.

It is these considerations, no doubt, that are preoccupying US military planners today. But while a final decision on these options may be put off for a time, the Defense Department cannot wait to make preparations for an assault if it expects to move swiftly once the President gives the go-ahead. Hence, it is taking steps now to prepare for the implementation of any conceivable plan.

The first step in such a process is to verify the location of possible targets in Iran and to assess the effectiveness of Iranian defenses. The identification of likely targets apparently began late last year, when the Central Intelligence Agency and US Special Operations Forces (SOF) began flying unmanned "Predator" spy planes over Iran and sending small reconnaissance teams directly into Iranian territory. These actions, first revealed by Seymour Hersh in The New Yorker in January, are supposedly intended to pinpoint the location of hidden Iranian weapons facilities for possible attack by US air and ground forces. "The goal," Hersh explained, "is to identify and isolate three dozen, and perhaps more, such targets that could be destroyed by precision [air] strikes and short-term commando raids."

It is also probable, says military analyst William Arkin, that CENTCOM is probing Iran's air and shore defenses by sending electronic surveillance planes and submarines into--or just to the edge of--Iranian coastal areas. "I would be greatly surprised if they're not doing this," he said in an interview. "The intent would be to 'light up' Iranian radars and command/control facilities, so as to pinpoint their location and gauge their effectiveness." It was precisely this sort of aggressive probing that led to the collision between a US EP-3E electronic spy plane and a Chinese fighter over the South China Sea in April 2001.

As this information becomes available, it is no doubt being fed into the various "strategic concepts" and "strike packages" being developed by US strategists for possible action against Iran. That such efforts are indeed under way is confirmed by reports in the international press that Pentagon officials have met with their Israeli counterparts to discuss the possible participation of Israeli aircraft in some of these scenarios. Although no public acknowledgment of such talks has been made, Vice President Dick Cheney declared in January that "the Israelis might well decide to act first" if Iran proceeded with the development of nuclear weapons--obviously hinting that Washington would look with favor upon such a move.

There are also indications that the CIA and SOF officials have met with Iranian opposition forces--in particular, the Mujaheddin-e Khalq (MEK)--to discuss their possible involvement in commando raids inside Iran or a full-scale proxy war. In one such report, Newsweek disclosed in February that the Bush Administration "is seeking to cull useful MEK members as operatives for use against Tehran." (Although the MEK is listed on the State Department's roster of terrorist groups, its forces are "gently treated" by the American troops guarding their compound in eastern Iraq, Newsweek revealed.)

Given the immense stress now being placed on US ground forces in Iraq, it is likely that the Pentagon's favored plan for military action in Iran involves some combination of airstrikes and the use of proxy forces like the MEK. But even a small-scale assault of this sort is likely to provoke retaliatory action by Iran--possibly entailing missile strikes on oil tankers in the Persian Gulf or covert aid to the insurgency in Iraq. This being the case, CENTCOM would also have to develop plans for a wide range of escalatory moves.

Repeating what was said at the outset, there is no evidence that President Bush has already made the decision to attack Iran. But there are many indications that planning for such a move is well under way--and if the record of Iraq (and other wars) teaches us anything, it is that such planning, once commenced, is very hard to turn around. Hence, we should not wait until after relations with Iran have reached the crisis point to advise against US military action. We should begin acting now, before the march to war becomes irreversible.