From NBC's Pete Williams and Jonathan Hutcheson
Did President Obama violate the Constitution or federal law when he ordered the U.S. military to take part in coalition attacks on forces loyal to Moammar Khaddafy in Libya?

The Constitution itself doesn't answer the question, because it gives Congress authority "to raise and support Armies," "to provide and maintain a Navy," and "to declare War." But it also provides that, "The President shall be Commander in Chief of the Army and Navy of the United States."

Congress has formally declared war only five times in U.S. history -- for the War of 1812, the Mexican War, the Spanish-American War, and World Wars I and II. But presidents have approved dozens of military actions with no such declaration, including the Korean conflict and the war in Vietnam. 

Well over 100 military operations were ordered without any advance Congressional authorization at all. Recent examples include actions in Grenada, the overthrow of Manuel Noriega in Panama, and intervention in civil wars in Bosnia, Kosovo, and Macedonia.

A federal law, the War Powers Act of 1973, requires the president to consult with Congress "in every possible instance" before deploying U.S. forces. An exception was made for emergencies created by attacks on the U.S. or its armed forces.

Some legal scholars conclude that President Obama violated the law's requirements, when he failed to seek congressional approval.

"Judging just from the pictures of what we are seeing happening on the ground, this is quite substantial, and this is the sort of thing that would have needed Congressional approval," said Professor Oona Hathaway of Yale Law School, an expert on executive power and international law.

While the president has stressed the international component of the operation, she believes that makes no difference. "The fact that the Security Council has authorized an imposition of a no-fly zone does not answer the constitutional questions," she said.

But one former official who advised President George W. Bush said that while the decision to deploy U.S. forces in the Libyan operation was a political and strategic mistake, it's entirely legal.

"Congress raises and supports the military, but the president is the commander. Declaring war and making war are two different functions. There's no question President Obama has the authority to do what he did," the official said, asking that his name not be used.

Mr. Obama's actions are consistent with the way every president since Richard Nixon has treated the War Powers Act, choosing to notify Congress only after a decision has been made to sign orders authorizing military operations.

His actions do, however, appear to contradict the view he expressed as a candidate. In December 2007, he told Charlie Savage, then of the Boston Globe that a president "does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation." 

So who's right? Constitutional questions, and legal battles over violations of federal laws, are normally resolved by judges. But this is an area where the courts have been reluctant to tread, unwilling to referee what they see as disputes between the political branches of the government.