War is an ugly thing, and it is understandable that a nation would enter it reluctantly. But once entered, it cannot be waged successfully in a timid or half-hearted way, without clear objectives and, especially for a world leader like the United States, without a leadership role.

All of which give us concerns as the United States now enters its third active military campaign.

Critics have complained for years about military campaigns they say ought to involve official declarations of war by Congress, as required by the Constitution. They tend to forget that even the Founding Fathers, when serving as president, waged military campaigns without formal declarations. For several years, Thomas Jefferson sent war ships to fight pirates in the vicinity of present-day Libya without such a declaration, although he received a congressional authorization similar to what President George W. Bush received before launching the war in Afghanistan. However, it seems appropriate now, given the length, cost and scope of the current campaigns, for the president to involve the people's representatives in a more formal declaration of assent to such use of the armed forces.

Perhaps that would force President Barack Obama to better define his intentions in Libya and, most important of all, what the endgame of that conflict would be.

On this, there appears to be much confusion. The president has said that Libyan leader Moammar Gadhafi must leave power. U.S. military officials, however, have joined with allies to say that Gadhafi is not a target of the bombing raids that commenced over Libya last weekend. Meanwhile, Adm. Mike Mullen, chairman of the Joint Chiefs of Staffs, said Sunday on Meet the Press that he could envision a solution in which Gadhafi remains in power. However, he did not elaborate on the many troubling questions such a position poses.

Could Libya be divided in two, with Gadhafi ruling over one side and some rebel leader over the other? Is the goal of the mission merely to put an end to Gadhafi's advances, rather than to secure a victory for the rebels? And, perhaps the most troubling question of all: Who are the rebels and what sort of leadership would replace Gadhafi were his regime to fall? On this point, Mullen said officials had been in touch with rebel leaders, but he offered little clarity as to their ultimate intentions.

The United States seems eager to turn command of the allied operation over to others within the coalition, and the president has ruled out the option of sending any ground troops. Some of the allies, however, seem eager to push agendas of their own. The French appear particularly aggressive and have already formally recognized rebel leaders as Libya's only legitimate government. If the United States cedes leadership of this mission, how can it be sure its interests are protected in the region?

President Bush absorbed a lot of criticism for his campaigns in Afghanistan and, particularly, Iraq, but he never wavered as to which nation was in charge or the objective of ousting current leaders.

That is one lesson to take from those wars. The other is that regime-change is only the start of such a mission. The campaign against Libya appears to be frighteningly devoid of any definable objective beyond merely stalling Gadhafi's advances. The United States and its allies act as if they can alter Gadhafi's behavior like a wayward child.

Rest assured that Gadhafi is deadly serious about his fight to retain power. For the rest of the world, it may be easy to define which side is noble and which is evil. But now that the rockets have begun to fly, the lack of a well-defined objective means things can get complicated in a hurry.