ON FRIDAY, under provisions of the War Powers Act, the 60-day authorization that went into effect when the United States committed forces to the mission in Libya will expire. Despite the longstanding disagreement between Congress and the executive branch over the legality of the law, both sides would do well to comply: The American public deserves the fullest possible explanation of the American role in Libya.

The 1973 Act, written with the lessons of the Vietnam War in mind, gives a president 60 days to commit forces without authorization by Congress. After that time, a president cannot introduce armed forces without a “declaration of war, a specific statutory authorization, or a national emergency created by attack upon the United States, its territories or possessions, or its armed forces.’’

There are currently no plans for either a committee hearing or a vote on a resolution based on the War Powers Act. Senators John Kerry and John McCain are still working on “consensus’’ language for a resolution expressing support for the military engagement.

Many books and articles have been written about the legality of the War Powers Act, and the courts have steadfastly refused to rule on the constitutionality of a law that attempts to divide the power to commit troops to battle between the two other branches of government: Congress and the president.

The White House has hinted it is prepared to comply with the act, or, in the words of Deputy Secretary of State James Steinberg, “to act consistent with the War Powers Act.’’ It may be that due to NATO’s lead in the effort, the Administration believes the War Powers Act does not apply. If that is the case, then they ought to say so.

But that by no means absolves Congress. Whatever the legal debates, the War Powers Act was intended to provide the American public, through Congress, with an opportunity to be fully informed about the use of military action. As refugees die, food runs out, Libyan rebels are accused of revenge killings, and the United States continues to fund part of the operation, Congress should require from the administration more details about US goals, more transparency about the costs, and some metrics for success in the absence of Moammar Khadafy’s removal — which is still not a stated reason for the military intervention.

Members of Congress ought not to neglect their duty to vote up or down on continuing involvement in Libya. Their silence can only be seen as willful abdication of their responsibility in a military action whose rationale that seemed so pure just 60 days ago.

© Copyright 2011 Globe Newspaper Company.