Captain Terry Kraft, commander of the aircraft carrier USS Ronald Reagan, sat in the mess hall during the Passover seder meal, a skullcap on his head, gefilte fish and hard-boiled egg on his plate, while the military chaplain, Joel Newman, conducted the ceremony. On a nearby wall, photographs of Ronald and Nancy Reagan stared down on the Jewish officers, sailors and their commanders.

Admiral William Fallon captured this scene, which took place last year, on film and then sent it to his Israeli friend, Major General (res.) Giora Rom. Fallon and Kraft are navigators. In the U.S. Navy, one does not have to be a fighter pilot to command an aircraft carrier, which is akin to a floating airbase, or the air wing that the ship hosts onboard.

Last year, Fallon was commander of PACOM, the U.S. Pacific Command. Now he is a lot busier, as commander of CENTCOM, Central Command, responsible for the fighting in Iraq, Afghanistan and, possibly in the near future, Iran.

Fallon has at his disposal two aircraft carriers in the Persian Gulf, the USS Eisenhower and the USS Stennis, each with a complement of 75 warplanes equipped with precise munitions. A third carrier, USS Nimitz, is making its way to the Gulf to replace the Eisenhower. During the overlap, all three will be within striking distance of Iranian targets, and the USS Reagan is not too far away.

This is enormous power, larger than the air forces of nearly all other countries, but it is also exposed to surface-to-sea missiles (like the Chinese-made C-802 cruise missile that Iran delivered to Hezbollah and which struck INS Hanit during the Second Lebanon War) and other threats, like the explosives-laden speed boat that seriously damaged the USS Cole, a destroyer anchored in the port of Aden in Yemen in 2000.

Naval hostile actions between the United States and Iran took place in the Gulf during the years 1987-88, as the Iran-Iraq war raged and Tehran targeted the tankers carrying Kuwait's export oil. This time, the clash may develop out of a crisis such as the Iranian ambush of a lackadaisical patrol of British sailors and marines, 15 of whom were captured without a fight on March 23 and who are expected to be released today.

In a major assault, American missiles will also be launched from submarines and underground silos in Colorado and South Dakota. But the aircraft carriers, whose visibility is almost conspicuous, have a clear advantage over missiles hidden from view: the element of deterrence they are supposed to create vis a vis Iran, and also an element of calm for the Gulf States, first and foremost Saudi Arabia.

However, the initiative is now in the hands of Iran, which is preferring not to wait for a time convenient for President George W. Bush to strike a blow following its refusal to cease its program to acquire nuclear weapons and the expected failure of diplomatic efforts to this end.

It is best for Iran to establish the context, the timing and the force of the clash with the West - a limited confrontation in the Gulf that could save it from a much bigger blow to its nuclear installations.

In a limited confrontation, Iran could lose the battle but win the campaign. At home, it will describe the shedding of American blood and the destruction of American equipment as an achievement, even if it pays a higher cost in loss of naval vessels, aircraft and oil installations.

The American public, Democrats in Congress and presidential candidates will protest and act to prevent any further escalation.

The Saudis and their neighbors will panic. The Bush administration, which is in the midst of a strategic pullout from Iraq (even if it is currently in a tactical offensive), will find it difficult to rally support for opening another front in Iran.

The ambush of the British sailors was an Iranian challenge, not the last one, to the U.S. and its allies. Bush is opposed in principle to deals involving prisoner exchanges for hostages.

He did not publicly voice his opposition to the release of Palestinian prisoners in exchange for Gilad Shalit. Nonetheless, a day before the British sailors were imprisoned, Secretary of State Condoleezza Rice criticized her Italian counterpart, Massimo D'Alema, for releasing five Taliban captives for an Italian journalist abducted in Afghanistan.

The London-Tehran deal sheds a strange light on Bush's declared principle. But had former U.S. president Jimmy Carter not failed in his efforts to release the hostages from the U.S. embassy in Tehran in 1980, Reagan, who is admired by Bush, would not have become president, been commemorated with an aircraft carrier, and have authorized an arms deal in exchange for the hostages in Iran.