The White House told Congress on Wednesday that President Obama is not in violation of the War Powers Act as the U.S. tries to drive Libyan leader Moammar Gadhafi from power because the U.S. is playing a NATO support role to enforce an international no-fly zone and is not engaged in combat.

A bipartisan group of House members went to court Wednesday to try to stop U.S. military involvement in Libya in what is ripening into a constitutional clash over the president's executive authority to commit military forces into a conflict without congressional approval. The White House on Wednesday sent a 32-page report and supporting materials, including classified information, to Capitol Hill, asserting that the president is operating within his authority and has regularly consulted with Congress, as required.

Early in June, the House approved a resolution that imposed a deadline of this Friday for the administration to explain in detail the U.S. objectives and actions in Libya. In a letter Tuesday, House Speaker John Boehner (R-Ohio) told Obama that if the administration does not either withdraw U.S. forces or obtain explicit authorization from Congress by Sunday, the president could be in violation of the 1973 War Powers Resolution.

Highlights from the administration's report to Congress:

- U.S. taxpayers, via existing Defense Department appropriations, have spent $716 million on military and humanitarian operations in Libya through June 3. Hundreds of millions more in humanitarian aid from the State Department also have been committed. The administration does not plan to ask for unbudgeted supplemental appropriations for Libya. Through Sept. 30, projected Defense Department costs are $1.1 billion for operations. The end of the second 90-day authorization by NATO falls on that date, as does the U.S. fiscal year.

- U.S. military involvement in Libya is justified to stabilize "a region pivotal to our security interests," to prevent "an imminent humanitarian catastrophe," and to show U.S. support for the people of the Middle East and North Africa during a time of transition.

- U.S. involvement in Libya to support NATO is seen as essential rather than optional. "The United States is providing unique assets and capabilities that other NATO and coalition nations either do not possess or possess in very limited numbers -- such as suppression of enemy air defense (SEAD); unmanned aerial systems; aerial refueling; and intelligence, surveillance, and reconnaissance (ISR) support. These unique assets and capabilities are critical to the successful execution and sustainment of NATO's ability to protect Libyan civilians and civilian populated areas from attack or the threat of attack and NATO's ability to enforce the no-fly zone and arms embargo."