With one short speech on Monday, Spanish prime-minister-elect Jose Luis Rodriguez Zapatero made official that his country, long one of Washington's staunchest supporters in the war, is considering withdrawing its forces from Iraq.

The prospect of losing a close ally is disquieting for the Bush administration, and on Monday, U.S. State Department spokesman Adam Ereli said the United States would consider drafting a new United Nations resolution aimed at providing the international body with a mandate to send troops to Iraq and assuage fears of the incoming Spanish government.

"The new (Spanish) government is just forming. They're formulating their policies. They'll be taking actions over the next couple of months. Simultaneously, there will be things happening in Iraq and in New York," he said.

But Ereli also questioned the need for a new resolution, arguing that the U.N. already has an Iraq mandate under a previously approved resolution. "It has been said that there needs to be a U.N. mandate for those troops," Ereli told reporters. "We believe there is such a mandate in (U.N. Resolution) 1511. At the same time, we've also said that, in the context of a transfer of sovereignty on June 30th, a new resolution is possible."

"The war in Iraq was a disaster"

On Monday, Zapatero (photo) criticized the U.S.-led invasion of Iraq, describing the war and occupation as a "disaster," and threatened to withdraw his troops by June 30 if a multinational U.N. force is not sent to the country. "The Spanish troops in Iraq will come home," Zapatero told a Spanish radio station.

Zapatero's position represents a 180-degree turn for Spain, whose outgoing conservative prime minister, Jose Maria Aznar, and his People's Party (PP) served as loyal backers of the U.S.-led invasion of Iraq, even though the majority of Spaniards opposed the war.

Though Zapatero ran his campaign on pledges to withdraw troops, the issue has taken on more urgency in Spain this week, with major public outrage following terrorist bombings of commuter trains in Madrid that killed 200 and wounded 1,500.

Initially, Aznar's (photo) government insisted the Basque terrorist organization ETA was responsible for the bombings, but recent evidence and arrests have shifted the focus of investigators to Islam extremists. With evidence suggesting ETA may not have been part of the attacks after all and that Aznar's government may have manipulated information with an eye on the polls, Spaniards turned their backs on the People's Party, instead voting in Zapatero and his anti-war platform.

Allies: We're staying put

Even as Spain appears to be preparing to exit Iraq, other members of the so-called "Coalition of the Willing," have come out quickly with statements offering their steadfast support for the occupation. Great Britain, Bulgaria, Denmark, the Czech Republic, the Ukraine and Japan have all said they would maintain their troops in Iraq.

If Spain pulled out its troops, Polish Prime Minister Leszek Miller warned, it "would amount to an admission that the terrorists are right and that they are stronger than the whole civilized world."

The Spanish pullout could have serious consequences for Poland. Currently, Warsaw is in charge of a 9,000-strong military contingent comprising 24 nations in south-central Iraq, including Spain's troops. Spain was expected to take control of the contingent in July, but those plans are now in question. Although Poland has said it could continue to command the troops, it would create an additional strain for the country.

A domino effect?

Spain's dramatic shift comes as a major setback to U.S. President George W. Bush's efforts to shore up support for his Iraq policies. The conservative PP is the first of Bush's allies to be ousted at the ballot box, and could leave other European leaders contemplating their next move in Iraq.

Observers, including Ted Galen Carpenter of the conservative Cato Institute in Washington, D.C., said if Washington is unable to keep Spain from removing its troops, it could lead to a "domino effect" in other countries where governments have supported the war but popular opinion has stood against it.