WASHINGTON — The apparent poison gas attack that killed hundreds of Syrian civilians last week is testing President Obama's views on military intervention, international law and the United Nations as no previous crisis has done.
The former constitutional law professor, who came to office determined to end what critics called the cowboy foreign policy of George W. Bush, now is wrestling with some of the same moral and legal realities that led Bush to invade Iraq without clear U.N. consent in 2003.
As U.S. officials discussed diplomatic and military options with allies in Europe and the Middle East, White House advisors indicated Tuesday that they were unlikely to seek either a vote in Congress or at the U.N. Security Council to authorize use of force. Last week, Obama said he had concerns about launching an attack on Syrian President Bashar Assad's government without a U.N. mandate.
Russia and China would almost certainly veto or delay any U.N. resolution condemning Syria or sanctioning reprisal. Top British and French officials, who are likely to support U.S. military action, have signaled they don't think a detour to the U.N. would be worthwhile.
White House Press Secretary Jay Carney said Tuesday that virtually no one doubted that Assad's government had carried out a chemical attack last week. But the Obama administration has yet to reveal the intelligence that led to that conclusion.
Syria's foreign minister, Walid Moallem, denied that government forces had used chemical weapons. "I dare them to produce any single piece of evidence," he said at a news conference in Damascus, the Syrian capital.
White House officials cautioned that Obama was still considering the options, but the administration appeared positioned to act quickly once he chooses a course. Defense Secretary Chuck Hagel said during a visit to Brunei that the Pentagon was prepared to strike targets in Syria and hinted that such a move could come within days.
Some experts said U.S. warships and submarines in the eastern Mediterranean could fire cruise missiles at Syrian targets as early as Thursday night, beginning a campaign that could last two or three nights. Obama leaves next Tuesday for a four day trip to Sweden and Russia, which strongly supports Assad's government, for the G-20 economic summit.
One U.S. official who has been briefed on the options on Syria said he believed the White House would seek a level of intensity "just muscular enough not to get mocked" but not so devastating that it would prompt a response from Syrian allies Iran and Russia.
"They are looking at what is just enough to mean something, just enough to be more than symbolic," he said.
Obama and his top aides have shared intelligence with key members of Congress. But White House aides made it clear Tuesday that Obama would not wait for Congress to return from its monthlong recess on Sept. 9, and House and Senate leaders signaled no plans to call members back for an emergency session.
"I can't imagine the president is going to do much more than the outreach he's already doing," said Jim Manley, former aide to Sen. Majority Leader Harry Reid (D-Nev.).
Sen. Carl Levin (D-Mich.), chairman of the Senate Armed Services Committee, said after a briefing that the administration was "proceeding cautiously." Obama is "considering a broad range of options that have been presented by our military leaders," he said.
Still, a growing number of lawmakers in both parties pressed the White House to seek authorization from Congress.
Rep. Scott Rigell (R-Va.) collected nearly three dozen signatures of House members on a letter he intended to send to the White House. It states that military action without a congressional vote "would violate the separation of powers that is clearly delineated in the Constitution." Congress stood ready to return for a debate on the issue, the letter says.
Other lawmakers worried that a few days of missile strikes might be counterproductive.
Sen. Christopher S. Murphy (D-Conn.), a member of the Foreign Relations Committee, said it would be "little more than a slap on the wrist" to the Syrian government, but could provoke retaliation from Assad that could draw America into "a much wider and much longer-term conflict that could mean an even greater loss of life within Syria."
Because of safety concerns, the team of U.N. inspectors in Damascus was forced to scrub a planned visit Tuesday to one of the suburbs allegedly hit by poison gas. They are to leave Syria on Sunday, but they probably will be withdrawn earlier if Washington warns that missile strikes are imminent.
"I would doubt" the United States or its allies would attack while the U.N. team was still in Syria, said Jean Pascal Zanders, a Belgian scientist and author of a blog that focuses on chemical weapons issues.
The U.N. team includes experts from the Organization for the Prohibition of Chemical Weapons and the World Health Organization. Led by a Swedish scientist, Ake Sellstrom, the investigators are seeking to determine if sarin nerve gas or other toxic agents were used in Syria, though not who used them.
British Prime Minister David Cameron has summoned Parliament to a special session Thursday. In addition to the British and French, Germany has indicated it could support military action if use of chemical weapons was confirmed. Turkey and Saudi Arabia, two regional foes of Assad, have indicated they could support a military response.
The Arab League said Tuesday that it had determined that the Syrian government was responsible, and it asked the United Nations to punish Damascus.
The White House has not put forward a legal framework for armed action in Syria, which has not threatened or attacked U.S. citizens or facilities, the usual justification for punitive strikes. Normally, nations may not use military force against other nations except in self-defense or when acting at the behest of the U.N. Security Council.
"Neither of those options is obviously in play here," said Ashley Deeks, a former State Department lawyer who teaches at the University of Virginia. She said the administration was looking at the 1999 intervention in Kosovo for legal precedent.
President Clinton joined with NATO allies in a so-called humanitarian war that targeted Yugoslav forces who had besieged Kosovo. Russia and China objected and called the "unilateral use of force … a flagrant violation" of the U.N. Charter. It took nearly three months of bombing to end the conflict.
Since then, lawyers who specialize in international law have been split over whether the United States must closely abide by international law or sometimes take military action to save lives.
Obama's aides include some who are wary of military action as well as backers of "humanitarian interventionism." Samantha Power, now the ambassador to the United Nations, repeatedly urged Washington to take bold action to stop genocide overseas before she joined government.
"Some people inside the administration have argued for a new legal doctrine that would say the United States has a legal right and an obligation to intervene to protect individuals who are being abused," said John B. Bellinger III, the State Department legal advisor under Bush. "But my guess is the president will see that as too risky, that a broad new doctrine could be used by others in ways that we don't foresee."
As recently as Thursday, Obama warned about intervening without U.N. support.
"If the U.S. goes in and attacks another country without a U.N. mandate and without clear evidence that can be presented," Obama told CNN, "then there are questions in terms of whether international law supports it. Do we have the coalition to make it work? Those are considerations that we have to take into account."
Over the weekend, as more evidence of a chemical attack surfaced, the White House dramatically changed its language.
Aides decided to clip references to a "U.N. mandate" and "international law" from the administration's talking points. Since then, Secretary of State John F. Kerry and Vice President Joe Biden have said Assad violated international "norms" regarding use of banned weapons.
Times staff writers David G. Savage, Shashank Bengali, Paul Richter and Ken Dilanian in Washington contributed to this report.
lanian in Washington contributed to this report.