WASHINGTON >> Defying congressional criticism, the White House insisted today that President Barack Obama has the authority to continue U.S. military action in Libya even without authorization from lawmakers on Capitol Hill.

In a detailed, 30-page report sent to Congress, the administration argued that the U.S. has a limited, supporting role in the NATO-led bombing campaign in Libya. Because U.S. forces are not engaged in sustained fighting and there are no troops on the ground there, the White House contended the president is within his constitutional rights to direct the mission on his own. 

It’s the first time the administration has publically detailed its legal rationale for continuing the Libya campaign without receiving congressional authorization within the 60-day window set in the War Powers Act. 

“The president is of the view that the current U.S. military operations in Libya are consistent with the War Powers Resolution and do not under that law require further congressional authorization because U.S. military operations are distinct from the kind of “hostilities” contemplated by the resolution’s 60-day termination provision.,” the White House said.

The report also put the cost of U.S. military operations and humanitarian assistance in Libya at about $800 million, as of June 3. Officials estimate U.S. costs in Libya will total $1.1 billion by early September.

The administration’s defense of the Libya mission comes in response to a nonbinding House resolution passed this month that chastised Obama for failing to provide a “compelling rationale” for U.S. involvement in Libya.

The resolution gave the administration until Friday to respond to a series of questions on the mission, including the scope of U.S. military activity, the cost of the mission and its impact on other U.S. wars in Iraq and Afghanistan.

It remained to be seen whether the administration’s reasoning would be enough to quell congressional criticism. Shortly after receiving the report, a spokesman for House Speaker John Boehner, R-Ohio, said the White House was using “creative arguments” that raised additional questions.

“We will review the information that was provided today, but hope and expect that this will serve as the beginning, not the end, of the president’s explanation for continued American operations in Libya,” spokesman Brendan Buck said.

A bipartisan group of 10 lawmakers stepped up the congressional pressure on Obama today, suing the president for taking military action against Libya without war authorization from Congress. The lawmakers said Obama violated the Constitution in bypassing Congress and using international organizations like the United Nations and NATO to authorize military force.

While Obama did not seek congressional consent before ordering U.S. airstrikes against Moammar Gadhafi’s forces nearly three months ago, the White House maintained that the president is not in violation of the War Powers Act. Boehner sent Obama a letter this week stating that the 90-day window runs out on Sunday. 

Previous presidents, Republicans and Democrats, have largely ignored the War Powers Act.

While the U.S. led the initial airstrikes on Libya, NATO forces have since taken over the mission. The U.S still plays a significant support role that includes aerial refueling of warplanes and intelligence, surveillance and reconnaissance work. Obama has ruled out sending U.S. ground forces to Libya. 

“U.S. operations do not involve sustained fighting or active exchanges of fire with hostile forces, nor do they involve the presence of U.S. ground troops, U.S. casualties or a serious threat thereof, or any significant chance of escalation into a conflict characterized by those factors,” the report said.

The president has said the U.S. joined the international effort in Libya to prevent the slaughter of civilians at the hands of Gadhafi’s forces, a development Obama said could have shaken the stability of the entire region. 

Though Obama emphasized that U.S. involvement would be limited in time and scope, the mission has already dragged on longer than many expected. The bombing campaign has halted some of Gadhafi’s advances on rebel forces and there are increasing calls from world leaders for him to leave power, but the administration is still struggling to define an exit strategy for U.S. forces.

The report released today said that if the U.S. were to end its participation in the NATO operation, it would “seriously degrade the coalition’s ability to execute and sustain its operations to protect Libyan civilians.”

The White House and Capitol Hill have been at odds throughout much of the campaign over whether the administration has fully consulted Congress on the mission. Congressional leaders and key committee members were only summoned to the White House the day before Obama ordered airstrikes against Gadhafi’s forces. Several lawmakers attended in person, others by phone as Congress had just begun a weeklong break.

Obama aides insist they have briefed Congress extensively throughout, citing more than 30 briefings with lawmakers and their staff, and 10 hearings where administration officials have testified on Libya. 

The White House has called the House resolution chiding Obama, as well as a similar resolution in the Senate, unhelpful and unnecessary. The administration much prefers a resolution sponsored by Sens. John Kerry, D-Mass., and John McCain, R-Ariz., that would signal support for the Libya operation.

The fate of that measure is in limbo, however, as the Senate Foreign Relations Committee delayed plans to discuss so lawmakers could review the House report.  

White House spokesman Jay Carney said Wednesday that the president expects Congress to support the Libya campaign as it continues. With Gadhafi under pressure to leave power, he said now is not the time to send “mixed messages” about U.S. commitment to the campaign.