|Republican leaders have lashed out at Obama for his continuation of US role in NATO-led Libya campaign [Reuters]
The White House insists that President Barack Obama has the legal authority to press on with US military involvement in Libya and urged sceptical legislators not to send "mixed messages" about their commitment to the NATO-led air war.
Senior administration officials, offering a detailed legal analysis to Congress to justify Obama's Libya policy, argued he had the constitutional power to continue the US role against Muammar Gaddafi's forces even though legislators had not authorised the mission.
Tensions in Washington over the Libya conflict reflected unease over US entanglement in a third conflict in the Muslim world in addition to wars in Iraq and Afghanistan and pressure for Obama to clarify US goals in the North African country.
The White House's defence of Obama's Libya policy followed a warning on Tuesday from John Boehner, the House speaker, that Obama was skating on thin legal ice by keeping US forces involved in Libya for nearly three months without direct congressional approval.
Boehner accused Obama of "a refusal to acknowledge and respect" the role of Congress in military operations and a "lack of clarity" about why the United States was still participating in the Libya campaign.
He asked Obama to explain the legal grounds for the war by Friday, saying that Obama by Sunday would be in violation of a 1973 law called the War Powers Resolution if nothing changed.
The US Constitution says that Congress declares war, while the president is commander-in-chief of the armed forces.
"We believe that it's important for Congress not to send mixed messages about a goal that we think most members of Congress share," Jay Carney, the White House spokesman, said on Wednesday, referring to hopes for the success of the NATO-led mission against Gaddafi's forces.
Ten members of Congress filed suit against Obama in federal court on Wednesday over Libya. The group, led by Democrat Dennis Kucinich and Republican Walter Jones, challenged Obama's decision to commit US forces to Libya without congressional authorisation.
"With regard to the war in Libya, we believe that the law was violated," Kucinich said in a statement.
Senior administration officials briefing reporters argued that Obama was not in violation of the War Powers Resolution because US forces, which initially spearheaded the assault on Gaddafi's air defences in March, had pulled back to a support role in the NATO-led air campaign in early April.
"We're not engaged in any of the activities that typically over the years in war powers analysis is considered to constitute hostilities," one official said. "We're not engaged in sustained fighting."
The law prohibits US armed forces from being involved in military actions for more than 60 days without congressional authorisation, and includes a further 30-day withdrawal period, which would expire on Sunday.
The White House's arguments seemed unlikely to defuse tensions with Congress over Libya, where rebels have made only halting progress against government troops and strains have emerged in the Western alliance.
Obama has also faced pressure from some NATO allies to take a more assertive military role in the conflict, but he has resisted and vowed no US ground forces would be deployed.
The debate over Libya comes as concerns grow in Washington over the costs and duration of the US-led war in Afghanistan, where Obama has pledged to start withdrawing troops in July.