The United States will enter a state of war with Syria if cruise missiles start flying, no matter what the operation is called.
War, in turn, will legally empower Syria to act in self-defense; perhaps, in some unexpected ways.
But while a U.S.-led attack appears increasingly likely, the legal underpinnings for lethal action remain ambiguous. Congress won't formally declare war. The last time it did that was 1941, when America entered World War II.
Lawmakers might consider authorizing force after they return from summer recess Sept. 9, but missiles could easily launch before then. Russian or Chinese resistance could block United Nations Security Council approval.
All of which add to the complications now confronting the White House.
"The president and his close advisers talk a lot about international law," Mary Ellen O'Connell, a professor of international law at the University of Notre Dame, said in an interview Monday, "so I don't see how the president can ignore that now without seeming to be hypocritical."
The Obama administration, though, has already shown a willingness to dance around legal restraints.
In March 2011, for instance, U.S. ships and warplanes began participating in an international air assault on Libya. The U.S. contribution to the six-month-long campaign included cruise missiles, drone strikes, bombers, fighters and more. Nonetheless, the State Department's top legal adviser insisted the actions didn't amount to "hostilities," a legally significant term.
Using logic that could recur with Syria, then-legal adviser Harold Koh told a skeptical Senate Foreign Relations Committee in June 2011 that the "limited exposure for U.S. troops, limited risk of serious escalation and . . . limited military means" meant the Libyan campaign didn't amount to hostile action. As a result, Obama asserted that he didn't have to comply with the War Powers Resolution's requirement that U.S. troops be withdrawn within 60 days of the start of hostilities unless Congress authorizes action.
"'Hostilities' is an ambiguous term of art," Koh testified.
Sen. Bob Corker of Tennessee, the ranking Republican on the Senate Foreign Relations Committee, countered at the time that the administration was "sticking a stick in the eye of Congress."
On Monday, speaking on MSNBC, Corker said he believes a U.S. "response is imminent" on Syria and added that he believes administration officials preparing for what he called a "surgical" military operation in the Middle Eastern nation of more than 22 million "do not need an authorization, but I hope they will come for one."
The War Powers Resolution permits the president to introduce U.S. forces into hostile action with a congressional declaration of war, a congressional authorization for use of force or in the event of a foreign attack on the United States or its forces. Once hostilities start, presidents have 60 days to act before they either remove the troops or get congressional approval.
In the international arena, two circumstances generally permit war making: national self-defense and action authorized by the U.N. Security Council.
Self-defense doesn't apply in the Syrian case, O'Connell said, because "the use of chemical weapons within Syria is not an armed attack on the United States."
Security Council authorization of international action requires the support of nine member nations on the 15-member panel. However, any of the five permanent members, which include China and Russia as well as the United States, can veto any proposed action. That seems likely in the case of Syria.
"Using force without the approval of the U.N. Security Council is a very grave violation of international law," Russian Foreign Minister Sergei Lavrov told reporters Monday at a Moscow news conference.
In 1999, Russia blocked U.N. Security Council support for military action in Kosovo, in the former Yugoslavia. The United States and other NATO countries, nonetheless, undertook a 78-day air war that ended with the withdrawal of Yugoslav forces.
Russia also resisted a 2003 Bush administration push for a key Security Council resolution targeting Iraq. As with Kosovo, the U.S.-led war proceeded regardless of the council's inaction.
"The U.N. Security Council is not the sole custodian of what is legal and appropriate," Council of Foreign Relations President Richard Haas said Monday, adding that the legitimacy of a U.S.-led attack "would rest on the case that Syria's use of chemical weapons violated international law."
On Monday, Secretary of State John Kerry did not elaborate on what legal basis might support a potential U.S.-led attack, but he also cited Syria's use of the "most heinous weapons against the most vulnerable victims." The word "heinous" is often invoked in international debate over chemical weapons.
The Chemical Weapons Convention bans the development, production and use of chemical weapons. The United States and 188 other nations have ratified this treaty. Others have not.
Israel signed the chemical weapons treaty but has not ratified it. Syria and four other countries, including North Korea, have neither signed nor ratified the treaty. Technically, this means Syria is not voluntarily bound by the treaty's proscription against chemical weapons production and use. O'Connell added, though, that the international opposition toward chemical weapons is sufficiently serious to provide meaningful sanctions against any country that uses them.
By Michael Doyle
McClatchy Washington Bureau