When Congress is confronted with the choice of exercising its war powers under the Constitution, its war dance is often a salsa sidestep—four steps left, four steps right, and lots of swaying back and forth.

This is especially true absent a presidential request to use force or overwhelming public sentiment for or against military action. Members prefer avoiding political risks when military failure is a possibility.

The latest U.S. military intervention in Libya to enforce the United Nations-authorized no-fly zone is no exception. Before the administration decided to support the draft Security Council resolution being circulated by France, some Hill critics chastised the president for indecisiveness and delay as Moammar Gadhafi's forces killed innocent protesters. Once the U.S. signed on to the UN Security Council resolution and helped secure its March 17 passage, the president was criticized for failing to consult Congress in advance and for not seeking prior Congressional approval.

It was not until the day after the UN vote and a day before the first airstrikes that the White House convened a bipartisan leadership briefing. Given the tight time frame, it is understandable why members complained the "consultation" was not what the War Powers Resolution contemplates—it was a done deal.

The confusion and distance between the branches only grew as the president left on a five-day Latin American visit and Congress headed home for a week's recess. The president did comply with the War Powers Resolution's 48-hour reporting requirement by notifying Congress on March 21 of "the commencement of operations." But the justifications in that letter only raised more questions.

On March 23, Speaker John Boehner sent the president a two-page letter in response. The Ohio Republican expressed respect for the president as commander in chief, but he indicated that he and many of his colleagues "are troubled that U.S. military resources were committed to war without clearly defining for the American people, the Congress and our troops what the mission in Libya is and what America's role is in achieving that mission." The letter went on to raise a host of specific questions.

When it became apparent that Boehner's concerns were shared by many on both sides of the aisle, the president cut short his Latin America trip by a day and headed back to Washington, D.C., to repair frayed communication lines. The White House immediately announced it would send top officials to the Hill to brief members the following Wednesday, March 30. It then pre-empted itself by announcing late Friday morning, March 25, that it would convene a briefing for members in person or by phone at 2 that same afternoon. That was followed Monday evening by the president's address to the nation on Libya.

The blizzard of briefings, speeches, press conferences, Congressional testimony and Sunday talk-show appearances by administration officials could not glaze over the underlying question of whether the president should have sought Congressional approval for the U.S. military operation. Then-Sen. Barack Obama's statement of Dec. 20, 2007, was again widely circulated: "The 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."

That statement is consistent with the language of the War Powers Resolution, which says the president may commit American troops to military hostilities only under a declaration of war or use of force authorization or in "a national emergency created by [an] attack upon the United States, its territories or possessions, or its armed forces." Yet every president since Richard Nixon (whose veto of the act was overridden) has declared the War Powers Resolution unconstitutional because it interferes with the president's prerogatives as commander in chief. Moreover, presidents cite as precedent dozens of unilateral military actions taken by their predecessors.

Most presidents have complied with the reporting requirements of the act. What they object to is the act's requirement to withdraw troops within 60 days unless Congress specifically authorizes their continued deployment. That withdrawal date for Libya is May 20. Senate Foreign Relations Chairman John Kerry (D-Mass.) says he is preparing the requisite resolution should it be needed.

Congress' previous attempts at flexing its muscles in such situations, without a presidential request for authorization, have usually been ineffectual or incomprehensible. The best example of this occurred on April 28, 1999, in response to President Bill Clinton's decision to commit U.S. planes to NATO-led airstrikes on Kosovo to prevent the massacre of ethnic Albanians. The House first passed a bill prohibiting the use of U.S. ground troops. It then defeated three resolutions calling for withdrawal, declaring war and supporting the airstrikes. Members gave themselves plenty of air cover with that spate of votes.

The current Libyan operation may not force members' hands if the president makes good on his promise of a limited engagement. In the meantime, though, it is causing a great deal of angst among those who have no desire for a third war.