The lifeboat problem involves five passengers (a pregnant woman, a confessed murderer, a navigator, an eminent scientist and a man just released after serving 20 years for a crime he didn't commit) and the need to jettison 200 pounds of humanity in order to keep the boat afloat.

The first two passengers weigh 150 pounds each; the other three are 200-pounders. Who gets tossed overboard?

If you are typical of my sophomore class that considered the problem a generation ago, you begin by sacrificing the underweight murderer, then you start thinking.

I am reminded of that ancient problem in ethics by our response to events in the Persian Gulf. We begin by figuring out how to dump Saddam Hussein, then we start thinking about the nature of our national interest in the region.

In the days immediately after the Iraqi annexation of Kuwait, the public debate revolved around two main options: protection of Saudi Arabia (and the world's oil supply) from further adventurism on the part of Iraq, or restoration of the pre-invasion status. But then the Bush administration started telling us what a brutal murderer the Iraqi leader is, and we added a third option: the elimination of Saddam, or at least the dismantling of his offensive military capability.

By now the consensus -- even on the part of those who, before the invasion, couldn't have named the president of Iraq on a bet -- is that Saddam has to go.

Maybe that's the right answer, but, as with the lifeboat problem, there are other considerations. Do we launch a war against Iraq and thereby risk the unraveling of the international consensus (including much of the Arab world) in favor of Operation Desert Shield? Would a strike on Iraqi forces trigger a counter assault on Israel? Does it make sense that the invasion force consist primarily of U.S. troops, perhaps with international moral and financial backing? In short, are the interests of the United States in the region sufficient to justify the risks of U.S. leadership in punishing Saddam?

President Bush is embarked on an international tour to make the case for action against Iraq. He might be better advised to try making the case at home. He hasn't made it yet.

To begin with the most direct U.S. interest -- oil -- a recent paper from the Cato Institute here argues that even the worst-case scenario, including Iraqi control of both Kuwaiti and Saudi oil supplies, would affect less than 16 percent of the world's oil production; much less of the U.S. consumption.

As for "world order," a U.S-led invasion of Iraq would, at least for the near term, create at least as much instability in the region as Saddam Hussein has managed. And because it would put the United States in the middle of an inter-Arab political squabble, it might make matters considerably worse both for us and for Israel, which remains the principal bone of contention between us and the Arab world.

Moreover, Iraq's threat to world order is a much more vital concern to the Middle East, and even to Western Europe and Japan, than to the United States. Why should we be the intrusive cop on somebody else's beat?

Perhaps the least attractive rationale for moving militarily against Iraq is the one forwarded by (among others) Henry Kissinger: that even questioning whether we should have moved our troops so massively into the region, the fact that they are there demands that they not be withdrawn until our stated objectives are accomplished. In other words, unless Saddam takes the humiliating option of backing down completely, we have to go to war because our troops have been deployed.

Nor is there much help for President Bush in the newest polls showing that Americans want Congress in on any decision to use the military option. One way to read those polls is that Americans don't believe that the facts as they know them justify the deaths of thousands of our fighting men and women.

America's realistic options, it seems to me, come down to two. Either allow Iraq some face-saving rationale for withdrawing -- perhaps by conceding the disputed oil fields on the Iraq-Kuwait border, or refashion our rationale to include an objective worth the risk of war: long-term peace in the region.

In this regard, the proposal of Michael Lerner in the current issue of Tikkun magazine has a lot to commend it.

Lerner's proposal is for an international conference to produce a three-prong plan: the dismantling of Iraq's offensive military capacity, the establishing of a demilitarized Palestinian state and a peace treaty between Israel and its Arab neighbors.

If Saddam bought into such an arrangement (and it might serve his purposes by making him the hero who solved the Palestinian problem) war could be averted. And if he didn't, there would finally be a persuasive rationale for dumping him overboard.