But any dispatch of Aegis destroyers would open a new constitutional can of worms.

Washington has informally asked Tokyo to help out with Aegis destroyers in the event of an attack on Iraq, a request that could be difficult for Japan to meet, government sources said Friday.

The request came at a Japan-U.S. working-level meeting on foreign and defense affairs.

U.S. representatives said they were counting on Japan to send Aegis warships and P3C anti-submarine patrol aircraft to the Arabian Sea to stand in for U.S. forces that would be moved closer to the action in the Persian Gulf if an attack were imminent.

However, Japanese government sources said this would be both politically and legally difficult under the constraints of recently adopted legislation allowing Japanese cooperation in the U.S.-led fight against terrorism.

Some officials said the special measures law would probably not be applicable to an attack on Iraq unless the assault targeted an al-Qaida terrorist network.

When U.S. President George W. Bush met Prime Minister Junichiro Koizumi in February, Bush said he would not rule out any option, including military strikes against Iraq. However, Bush also pledged to continue diplomatic efforts to reach a less violent conclusion.

Aides to Koizumi said they are not taking Washington's requests at the working-level talks terribly seriously because the U.S. side did not push very hard.

At any rate, Washington currently has its hands full trying to facilitate some sort of truce between Israel and the Palestinians and any move against Saddam Hussein is not expected any time soon.

In any question of military assistance, constitutional issues always loom large in Tokyo, and even more so when state-of-the-art Aegis destroyers are involved.

With their advanced information systems, Japanese Aegis vessels can share real-time battle data with sister ships in the U.S. Navy. This capability is sure to incite objections by opposition parties if Koizumi tried to dispatch a flotilla to the Arabian Sea.

Any political uproar over Iraq would be unwelcome right now as the Koizumi Cabinet is devoting its energies to pushing three controversial bills dealing with military attacks on Japan through the Diet during the current session.

After the Sept. 11 terrorist attacks, Washington informally asked Tokyo to dispatch Aegis destroyers to the Indian Ocean to support the U.S.-led strikes against the Taliban and al-Qaida in Afghanistan.

The request ignited a political brushfire even inside the ruling coalition.

However, the rapid collapse of the Taliban regime last November-an event unlikely to repeat itself in the case of an assault on Iraq-sucked much of the oxygen out of the debate.