Just three days after the House overwhelmingly rejected a similar step, the Senate Foreign Relations Committee endorsed a resolution to authorize the effort against Moammar Gadhafi's forces for one year while prohibiting U.S. ground troops in Libya. The vote was 14-5 and muddled the message emerging from Congress about the American role in the NATO-led operation.
Sen. John Kerry, D-Mass., the panel's chairman, said the bottom-line question three months into the conflict and with Gadhafi "bunkered down in Tripoli" and facing an arrest warrant from the International Criminal Court is: "Do we want to stop the operation?"
He called passage of the resolution a critical step that would send a message around the world.
The full Senate is expected to consider the resolution the week of July 11.
The panel's top Republican, Sen. Richard Lugar of Indiana, opposed the measure, arguing that with the U.S. at war in Iraq and Afghanistan, the nation's debt in the trillions of dollars and no vital interests in Libya, "I do not believe that we should be intervening in a civil war there."
The panel's action followed testimony by Harold Koh, the State Department's top lawyer, who said Obama acted legally in ordering U.S. military action against Libya because the conflict is neither a war nor full-blown hostilities.
Koh also warned that abandoning the mission now would undermine U.S. relationships with allies and "permit an emboldened and vengeful Moammar Gafhafi to return to attacking" Libyan civilians.
Koh faced Republicans and Democrats who challenged his assertion that air strikes and drone attacks on Gadhafi's forces do not constitute hostile action.
Lawyers from the Pentagon and Justice Department declined the panel's invitation to testify.
"The fact that we are leaving most of the shooting to other countries does not mean that the United States is not involved in acts of war," Lugar said. "If the United States encountered persons performing similar activities in support of al-Qaida or Taliban operations, we certainly would deem them to be participating in hostilities against us."
Sen. Jim Webb, D-Va., a decorated Vietnam War veteran, questioned the administration's "narrow and contorted definition of hostilities," adding that an operation that lasts for months, costs millions of dollars and involves combat pay for troops offshore amounts to hostilities.
Sen. Bob Corker, R-Tenn., called it a "cute argument" that has undermined the administration.
Obama angered lawmakers by ordering air attacks on March 19 and then failed to seek congressional approval for the action within 60 days, as established by the 1973 War Powers Resolution, or end the operation. In a report to Congress earlier this month, the administration said Libya does not amount to full-blown hostilities and congressional consent is unnecessary, further incensing members of Congress.
Koh said four factors led Obama to conclude that the Libya operation did not fall within the War Powers law. The lawyer said the military's role is limited - in mission, exposure of U.S. troops to hostilities, risk of escalation and military attacks.
"We believe that the president is acting lawfully in Libya, consistent with both the Constitution and the War Powers Resolution, as well as with international law," Koh told the committee. "Our position is carefully limited to the facts of the present operation, supported by history, and respectful of both the letter of the resolution and the spirit of consultation and collaboration that underlies it."
He added: "Nor are we in a war."
Koh said the War Powers Resolution does not define hostilities, and neither the courts nor Congress have spelled it out.
Kerry pointed out that the resolution was passed in response to Vietnam, then the nation's longest conflict in which more than 58,000 Americans died yet Congress never declared war. Nearly 40 years later, the U.S. operation in Libya involves unmanned Predator drones, a weapon the military could only imagine in the 1970s.
Since NATO took command of the Libya operation in early April, the U.S. role has largely been limited to support efforts such as intelligence, surveillance and electronic warfare. The U.S. has launched airstrikes and drone attacks, flying more than 3,200 sorties. The effort has included some 39 drone attacks and 80 strikes with jet fighters.
"In Libya today, no American troop is begin shot at," Kerry said in backing the administration argument.
Koh acknowledged the widespread disagreement over Obama's rationale for not seeking congressional authority, but said the critical question was not of law but policy: "Will Congress provide its support for NATO's mission in Libya at this pivotal juncture, ensure that Gadhafi does not regain the upper hand against the people of Libya?"
Koh, who served as assistant secretary of state for democracy, human rights and labor in the Clinton administration and then became dean of Yale Law School before returning to government service under Obama, has been criticized and praised by conservatives. As dean at Yale, Koh was highly critical of the Bush administration's use of enhanced interrogation techniques of terror suspects and their imprisonment at the U.S. naval prison at Guantanamo Bay, Cuba.
However, he earned plaudits from some conservative opponents when he argued forcefully for the legality of the Obama administration's targeted airstrikes, using both drones and piloted aircraft, against terrorists.