Washington and Tel Aviv must confront the reality that this war cannot be won militarily, even stretching to the limit and beyond the constraints imposed by international humanitarian law. The only way out is diplomatic and political. It begins with an immediate cessation of hostilities, followed by a prisoner exchange and, under appropriate conditions, the dispatch of an international force to South Lebanon. Given Lebanon's history and its fragile political-sectarian balance, any such force must be contemplated with extreme caution. It has to be agreed to by all parties—Hezbollah included—authorized by the U.N. Security Council, and be a confidence builder, not an enforcer. Understandable as the desire of Israel and the United States may be to have a force with full disarmament powers, if it is viewed as threatening Hezbollah or taking sides in the confessional battles it could plunge the country into a new round of civil strife.

But, the United States says, stopping violence is not enough unless we deal with what the administration calls "root causes." Indeed. Yet it posits a dubious zero-sum choice: Either we tend to those causes now, while violence flares, or we never will. Surely there is no reason why the administration, applying its considerable power, could not mobilize international energy to address these underlying problems once a cease-fire has been secured—no reason, of course, other than that it has shown no such appetite for diplomacy in the six years preceding the crisis. Just as there was no reason to wait for violence to break out before tackling root causes, there is no reason to wait for root causes to be tackled before ending violence.

Then there is the question of identifying these root causes. The administration singles out Hezbollah's existence as an autonomous armed militia and concludes that to knock it out is the answer. Hezbollah's capability is a part of the problem, and not a negligible one at that. But a root cause? The root cause? Can this really be the U.S. view of the crisis engulfing the region?

To find root causes one has to dig deeper. There are reasons why Hezbollah has risen and prospered and why it has been so difficult to disarm. These relate to the disadvantaged status of Lebanon's large Shiite constituency and to the fact that many among them view the Islamist movement as their principal asset in an otherwise inequitable political system. To aggressively go after Hezbollah without simultaneously addressing Shiite grievances could push the fragile nation to the breaking point. Hezbollah's clout also can be attributed to still-unresolved Israeli-Lebanese matters, including the contested Shebaa Farms, which the Islamist movement readily invokes as justification for retaining its arms. And Hezbollah's fate is closely intertwined with regional issues, including Syria and Iran's role, and the failure to activate a comprehensive Arab-Israeli peace.

A serious effort to safeguard Israel's security without jeopardizing regional or Lebanese stability is possible, but only if the United States is prepared to engage in vigorous, continuous, and comprehensive diplomacy. Immediately after a cease-fire has been secured, the United States and its European and Arab partners should focus on ending the conditions that produced this deadly conflagration—the real root causes. This would include intensifying the intra-Lebanese dialogue concerning Hezbollah, as well as the country's political system and national defense; addressing pending Israeli-Lebanese issues; engaging Syria and Iran in a broad discussion of regional matters; and reinvigorating the long-dormant Arab-Israeli peace process.

Deal with root causes? By all means, as many of us have been arguing for years. But the right ones, and all of them, and in a way that doesn't postpone the most urgent priority of all—stopping the present killing