Many Lebanese will be angry at Hizbullah's leader, Sayyed Hassan Nasrallah, for provoking the crisis, but that won't translate into new control of the militia's actions. Instead, the outcome is likely to be similar to what has happened in Gaza over the past several weeks, where Israeli attacks to free a captured soldier further weakened the Palestinian Authority without much damaging the terrorists.

Watching the events of the past few days, you can't help but feel that this is the rerun of an old movie -- one in which the guerrillas and kidnappers end up as the winners. Israel's fledgling prime minister, Ehud Olmert, wants to emulate the toughness of his predecessor, Ariel Sharon, but that shouldn't include a replay of Sharon's 1982 Lebanon invasion, a strategic mistake that spawned Hizbullah in the first place.

Hizbullah's action in seizing the Israeli soldiers was utterly reckless. That's the new part of this crisis -- that Iranian-backed radicals deliberately opened another front in a war that, in their minds, stretches from Gaza to Iraq. Watching Nasrallah's performance at a news conference Wednesday, he seemed almost to be inviting an Israeli counterattack -- knowing it would destabilize the Lebanese government of Fouad Siniora, whose establishment in the wake of the Syrian withdrawal last year was one of the few solid achievements of US policy in the region.

Israeli and American doctrine is premised on the idea that military force will deter adversaries. But as more force has been used in recent years, the deterrent value has inevitably gone down. That's the inner spring of this crisis: The Iranians (and their clients in Hizbullah and Hamas) watch the American military mired in Iraq and see weakness. They are emboldened rather than intimidated. The same is true for the Israelis in Gaza. Rather than reinforcing the image of strength, the use of force (short of outright, pulverizing invasion and occupation) has encouraged contempt.

The danger of Iranian-backed adventurism is immense right now, but that's all the more reason for America and Israel to avoid past mistakes in countering it. Reliable strategic lessons are hard to come by in this part of the world, but here are a few.

The first is that in countering aggression, international solidarity and legitimacy matter. In responding to the Lebanon crisis, the United States should work closely with its allies at the G-8 summit and the United Nations. Iran and its proxies would like nothing more than to isolate America and Israel.

A second point -- obvious from Gaza to Beirut to Baghdad -- is that the power of non-state actors is magnified when there is no strong central government. That may sound like a truism, but responding wisely can require some creative diplomacy. The way to blunt Hamas is to build a strong Palestinian Authority that delivers benefits for the Palestinian people. The way to curb Hizbullah is to build up the Lebanese government and army. One way to boost the Lebanese government (and deflate Hizbullah) would be to negotiate the return of the Israeli-occupied territory known as the Shebaa Farms. That chance is lost for now, but the Bush administration should find other ways to enhance Siniora's authority.

A final obvious lesson is that in an open, interconnected world, public opinion matters. This is a tricky battlefield for an unpopular America and Israel, but not an impossible one. To fight the Long War, America and Israel have to get out of the devil suit in global public opinion. For a generation, America maintained a role as honest broker between Israel and the Arabs. The Bush administration should work hard to refurbish that role.

In the Lebanon crisis, we have a terrifying glimpse of the future: Iran and its radical allies are pushing toward war. That's the chilling reality behind this week's events. On Tuesday, the Iranians spurned an American offer of talks on their nuclear program; on Wednesday, their Hizbullah proxy made what Israel rightly called "an act of war." The radicals want to lure America and Israel deeper into the killing ground, confident that they have the staying power to prevail. We should not play their game.