WASHINGTON – President Obama missed a legal deadline Friday — set in a 1973 law — that required him to obtain congressional approval for U.S. military operations in Libya.

Friday was the 60th day since Obama formally notified Congress that U.S. planes would strike targets in Libya, a bid to protect civilians from the government of strongman Moammar Gadhafi. Under the Nixon-era War Powers Resolution, the president must obtain congressional authorization of military action within 60 days or else begin withdrawing forces.

Neither happened. Instead, in a letter sent Friday night to congressional leaders, Obama expressed support for a proposed resolution that “would confirm that Congress supports the U.S. mission in Libya.”

DOES RESOLUTION APPLY?

The president also described U.S. military efforts as “more limited” than in the campaign’s early days. He said they include providing logistical and intelligence help to the NATO-led operation, as well as supplying aircraft and unmanned drones to attack Libyan targets.

Obama did not, however, explicitly say whether he thinks the War Powers Resolution applies to the Libyan operation. That act makes no specific exception for limited or supporting action: It applies to any instance in which military forces are “introduced into hostilities,” or sent into foreign territory or airspace while equipped for combat.

Congressional leaders have showed little desire to challenge Obama on the deadline. Presidents Reagan and Clinton also had not obtained congressional approval for overseas actions, with little repercussion from Capitol Hill.

After Obama sent his letter, Jon Summers, a spokesman for Senate Majority Leader Harry Reid, D-Nev., said only that “Senator Reid has received the letter and is giving it his full consideration.”

An aide to House Speaker John Boehner, R-Ohio, said the lawmaker had not seen the draft resolution that Obama mentioned. “No decisions will be made until such a review takes place and we discuss the matter with our members,” Michael Steel wrote in an email.

But the resolution has not been formally introduced, said a spokeswoman for Sen. John McCain, R-Ariz., one of a group of senators whom Obama cited as its sponsors. Brooke Buchanan said the draft expresses general support for the operation in Libya and contains no mention of the War Powers Resolution.

INACTION MEANS ‘NIXON WON’

Legal scholars say that congressional inaction could severely weaken a law intended to take back legislative control of U.S. warmaking.

“Before we engage in a serious military endeavor, both branches should give their consent,” said Bruce Ackerman, a Yale University law professor. If Obama ignores the law, he said, “we go back to the status quo before 1973. I mean, Richard Nixon will have won.”

The War Powers Resolution was an attempt to settle a dispute as old as the Constitution. That document says only Congress has the power to declare war but the president is commander in chief of the military.

Presidents construed that to mean they could send U.S. forces into combat without congressional approval. The reasoning was that the fights would be too small to be viewed as a “war.”

In 1973, Congress tried to take back its power. But almost since the War Powers Resolution was written, presidents have been trying to ignore it. Many have argued that it is unconstitutional, usurping presidential powers to command.

In 1982, Reagan sent Marines into Lebanon and kept them there for a year without official congressional approval. Congress finally passed a resolution authorizing him to continue for 18 more months.

In 1999, during the conflict in Kosovo, Clinton authorized U.S. airstrikes on Yugoslavia. The 60-day deadline passed, with no explicit permission from Congress (although lawmakers did provide funding for the strikes). The air campaign ended after 78 days.