President Bush should seek to devise a way to involve Congress in the Persian Gulf crisis without restricting his options or authority as commander in chief. Fortunately, just such a mechanism exists: a conditional declaration of war authorizing the president to take military steps if certain specified conditions are met.

While previous presidents have acted unilaterally, and almost certainly unconstitutionally, in committing military forces without congressional consent, such cases cannot justify this president's acting lawlessly. Bush - if he takes the Constitution seriously - has to gain congressional authorization for an attack against Iraqi forces.Unlike a declaration of war, a conditional declaration would not signal imminent hostilities. Rather, like a United Nations resolution, it would provide the legal basis for future offensive action. The war-making decision would still rest primarily with the president.

Although long-since forgotten, a conditional declaration would not be unprecedented. In fact, Congress passed conditional declarations of war on four separate occasions.

Involving Congress would have several advantages. First, the president would have to decide on his goals and articulate what he expects war to achieve.

When he frets over a possible Iraqi nuclear weapon, for example, he suggests his objective is overthrowing Saddam Hussein rather than liberating Kuwait. The uncertainty over what Bush intends not only makes it harder for him to unite this country but also leaves Hussein uncertain as to exactly what step or steps will avert war.

Second, going to Congress would fulfill the Constitution's dictates by allowing the people's representatives to decide whether the president's goals warrant war. This is particularly important since the president's strategy resembles a giant bait-and-switch operation - he has moved from defensive to offensive objectives without bothering to acknowledge, let alone explain, the change.

Congress could ratify Bush's course, decide for a limited war (to free Kuwait but not conquer Iraq, for instance) or say no, forcing the administration to rely on sanctions.

Third, a congressional debate would allow the American people to voice their opinion. Polls suggest average citizens are less interested in fighting to defend cheap gas, feudal aristocracies, jobs and a utopian new world order than are State Department officials and think-tank analysts. If the president believes his objectives are worth a war he should spell them out and subject them to a full and fair debate.

Bush's apparent willingness to sacrifice thousands of lives for dubious goals cannot be beyond debate. Moreover, by law the final decision on war rests with Congress.

Although such constitutional niceties may seem unduly restrictive in the modern age, respect for the law is the most fundamental difference between a free society such as our own and a totalitarian sinkhole such as Iraq.