"You know, they blew up the Maine," the president said in his familiar, offhand manner, by way of illustrating why presidents should never say never when it comes to the question of committing American forces to foreign wars. The press conference turned to the question of whether he is a rich man's president and a 15th futile effort to find out what he knew about Jimmy Carter's briefing book and when did he know it. Time ran out before anyone asked him precisely why he wanted us to remember the Maine.

Yet the president could hardly have employed a more arresting, not to say explosive, analogue. And he could hardly have picked a less propitious time to incite debate and heighten anxiety over how, and by whose hand, American forces are committed to combat in a foreign land. Even as the president was speaking, congressional critics of his Central America policy were already struggling to constrain the creeping "Americanization" of the counterinsurgency efforts of the army and government of El Salvador.

Meantime, the foreign policy powers-that-be on Capitol Hill were assessing the damage done to the War Powers Act by the recent Supreme Court ruling that the congressional veto is unconstitutional. Hardly the time, one would have thought, to be hauled all the way back to Havana harbor in 1898 and the explosion that sank the U.S. battleship Maine.

For if the public frenzies and abuses of power in that egregious episode are to be our guide, the president was opening up a loophole large enough for the 82nd Airborne and several battalions of U.S. Marines even as he was "seeing no need" for American combat forces in Central America. It's true, there is one crucial connection: high-profile American military presence in the vicinity of an armed conflict. The Cubans were in revolt against Spanish rule. And, true, the Maine blew up.

There was no evidence of who "they" were who did it. But some 250 American sailors died, and that was grounds enough for Teddy Roosevelt, as assistant secretary of the Navy, to blame Spain and exploit a willing press to fan the flames of war. Carried along by public hysteria, an overheated Congress announced Cuba's independence, authorized intervention by American forces and ultimately declared war. Thus began the first (and final) American fling with imperialism.

All this, and more, is set down in Merlo Pusey's primer on "The Way We Go to War": heavy-handedly, and more often than not unconstitutionally, Pusey concluded. With remarkable prescience he argued that "under the impact of ideological upheavals and sudden acquistion of superpower responsibilities, we have drifted a long way from the restraints that the founding fathers put upon war making"--by which he meant the authority vested in Congress to "declare" war.

The prescience was in the timing: Pusey's book came out in 1969; just one year later Richard Nixon arrogantly expanded the Vietnam War (itself undeclared)--with no prior notice to Congress--by ordering a surprise American attack across the borders of neighboring Cambodia. The targets were "enemy" concentrations of North Vietnamese forces in privileged Cambodian sanctuary.

But the consequences to Cambodian political stability were catastrophic, and the political impact in the United States was to be profound. For it was the Cambodian "incursion," according to a House report of the legislative history, that provided the "initial impetus for a number of bills and resolutions on the war powers" that culminated in the passage of the War Powers Act in 1973. Its provisions would permit the president to commit troops to hostile situations, even without necessarily consulting Congress in advance, though that is the law's clear preference. It also provides that if the troops are not withdrawn within 60 days, Congress must authorize their continuing presence by legislation.

Finally, if Congress disapproves of the mission, it assumes the right to veto it, which would require the president to withdraw the forces.

Most legal experts seem to agree that this last feature of the act has been wiped out by the Supreme Court's ruling on legislative veto power.

So now the lawmakers, already wrestling with the Central American case in hand, must address themselves to the larger question of how to strike a reasonable and effective balance between the war-making powers, rights and responsibilities of Congress and the executive. They will find scant inspiration in the past, whether recent, as in Vietnam and the murky matter of the Tonkin Gulf incident, or remote, as in the equally dubious origins of the Spanish-American War. But they will find useful lessons.

Merlo Pusey did. "If Congress will not authorize a war, limited or full-fledged, after reasonably full knowledge of the facts and sober deliberations, the American people should not be in it," he wrote. "Our first and largest constitutional obligation . . . is to move toward restoration of that principle."