“With all due respect, I can only conclude that your order to United States Armed Forces to attack the nation of Libya on March 19, 2011 is in direct violation of the War Powers Resolution and constitutes a usurpation of constitutional powers clearly and solely vested in the United States Congress and is accordingly unlawful and unconstitutional,” wrote McClintock.

The second-term congressman said Obama had failed to explain in his letter announcing his actions to Congress how the U.S. military action was justified. Obama is enforcing a United Nations resolution that allows measure to be taken by the international community to stop violence against civilians in Libya.

“The Constitution clearly and unmistakably vests Congress with the sole prerogative ‘to declare war,’” continued McClintock. "Your letter fails to explain how a resolution of the United Nations Security Council is necessary to commit this nation to war but that an act of Congress is not.”

Members of both parties have criticized Obama for not consulting more with Congress before his decision. Speaker John BoehnerJohn Andrew BoehnerJim Jordan as Speaker is change America needs to move forward Paul Ryan’s political purgatory Republicans fear retribution for joining immigration revolt MORE (R-Ohio) in a Wednesday letter said he respected Obama’s “authority as commander in chief,” but regretted there had not been more consultation.

McClintock wrote that Obama’s letter to Congress failed to explain how he had met criteria laid out in the War Powers Resolution of 1973. That act was a joint congressional resolution that empowers the president to send armed forces into action abroad only with authorization of Congress or if the United States is already under attack.

“The War Powers Resolution unambiguously defines three circumstances under which the president as commander in chief may order United States Armed Forces into hostile action,” wrote McClintock. “(1) a declaration of war, (2) specific statutory authorization, or (3) a national emergency created by attack upon the United States, its territories or possessions, or its armed forces. Your letter cites none of these conditions.”

As of publication, McClintock’s office had not received a response from the White House.