I'm not sure I understand the debate over the War Powers Act. It isn't clear to me whether it's a question of hawks vs. doves, of Republicans vs. Democrats, or of macho men vs. nervous nellies. I'm certain that I don't understand the compromise that says the president can send the Marines into combat if he chooses, but only for 18 months. After that, Congress will start thinking about invoking its constitutional power to declare (or not declare) war.

But one thing does seem fairly clear to me, though it seems to be no part of the current debate: before you go to war--before you get yourself in a situation where you will likely have to shoot and be shot at--it makes sense to have a pretty fair idea of who your enemy is. Who is our enemy in Lebanon? Our friend, one supposes, is the Gemayel government. But who are our enemies? The Syrians, who seem to be in control of a huge hunk of northern Lebanon and who seem intent on blocking peace negotiations? The Druze and their Palestinian allies, upon whom our battleships opened fire a couple of weeks back? The Christian Phalangists, whose massacre of Palestinian men, women and children in the Sabra and Shatilla refugee camps led to our dispatch of the Marines (part of a multinational force) in the first place? The Israelis, whose invasion of Lebanon helped to further destablize that state? Some combination of the various Moslem or Christian sects.

The official answer is that we have no enemy in Lebanon. We are there not to prosecute a war but to preserve the peace. Fine. But when one of the factions attacks the Lebanese government, on whose behalf we are (presumably) keeping the peace, and we open fire on that faction in order to protect the government, haven't we just bought ourselves an enemy? And if this multifactional civil war continues for much longer, aren't we likely to buy ourselves other enemies? And won't we then come under pressure, both there and at home, to do what is necessary to defeat those enemies?

In short, the line between keeping peace and making war is not all that clear, and the sinking feeling is that we may already have crossed it. But not necessarily irrevocably. The cease-fire that went into effect on Monday provides at least a chance of a negotiated settlement among the parties to the Lebanese war-- and a chance for the United States to find a way to get its troops out. We clearly ought to do what we can to assist those negotiations, including keeping the Marines in place for yet a while longer.

The trick is how to help bring peace among the warring factions without becoming one of the warring factions if the peace effort fails. Maybe the only way out is to find some way of turning the peacekeeping duty over to the United Nations--preferably without the direct involvement of U.S. troops. Meanwhile, the debate on Capitol Hill, while of doubtless constitutional significance, seems to have nothing to do with what we ought to be doing in Lebanon. That argument has to do with how, and by whose authority, we are to go to war. In the case of Lebanon, the fact that we don't have an enemy there strikes me as a pretty good reason not to get into the war.