By entrusting one of its most dangerous fronts to a U.N.-led force, Israel is rethinking a principle that has guided its security policy for generations.

In 1978, the United Nations deployed the U.N. Interim Force in Lebanon, which, as its name suggests, was to stay in southern Lebanon for an “interim.” But UNIFIL remained, as an ineffective and biased observer, through significant changes in Lebanon.

Does UNIFIL-plus, the new European-led force now being deployed in southern Lebanon, have an exit strategy? Will it remain “enhanced” by European troops? What happens after the first deadly skirmish between Hezbollah and the Europeans? What does the force do if Israel decides to fly a drone over southern Lebanon? What if Israeli troops cross the border?

Generations of Israeli officials with similar questions have eyed the prospect of an international presence on their border with suspicion. Such a presence, they have reasoned, would be more sympathetic to its host, like Hezbollah, than to Israel.

Jerusalem has steadfastly resisted any solution involving an international force that might limit the Israel Defense Force’s ability to act militarily. Now, the Italian foreign minister, Massimo D’Alema, is saying that following the troop deployment in Lebanon, a similar international force should go to Gaza, as well. And Palestinian Arab officials agree.

As many Israelis often ask, what would Arik do?

A deputy national security adviser to Prime Minister Sharon, Chuck Freilich, told me recently that strategic planners had floated the idea of sending U.N. troops to Gaza several times before last August’s Israeli withdrawal. Mr. Sharon “wasn’t willing to consider it then and I can only guess he wouldn’t have considered it now,” Mr. Freilich said.

However, as Israel ended its blockade of Lebanon last week and entrusted an international naval force to ensure that Hezbollah does not rearm or smuggle kidnapped Israelis to Iran, many feared that decisions in Jerusalem are being made on the fly, without any deep strategic thinking. “What did we go in for, to bring in an international force?” Mr. Freilich said.

Foreign Minister Tzipi Livni told a small group of reporters recently that the United Nations offers the least bad among many bad solutions. “What do you want to do, have the IDF deployed on the Syrian-Lebanese border for decades?” she said.

For now, Jerusalem’s renewed faith in Turtle Bay has not been rewarded — UNIFIL reports that Israel has made the vast majority of the cross-border violations of U.N. Security Council resolution 1701.

Cross-border IDF flights count as violations, while Hezbollah’s refusal of even Red Cross visitation to the two kidnapped Israeli soldiers does not. Disarming Hezbollah is defined for now as a wished-for consequence of the “political process” rather than a hard Security Council demand.

Although Deputy Secretary-General Mark Malloch Brown crowed to CNN yesterday that the United Nations is engaged in a “highly confidential, discreet mission” to help free the kidnapped Ehud Goldwasser and Eldad Regev, a Hezbollah official, Mahmoud Kamati, told the Nazareth-based newspaper A-Sinara on Friday that his organization has “yet to receive a formal approach from the U.N.” on the issue.

That same day, Secretary-General Annan told reporters that he is aiming to secure “the release of the two abducted Israeli soldiers and the release of the Lebanese prisoners.” The Security Council’s demand for the Israelis to be released “unconditionally” has been dropped, however. In his effort to get close to those within Hezbollah with access to the kidnapped soldiers, all Mr. Annan has done so far is publicly give away possible negotiating points.

Their boasts aside, Sheik Hassan Nasrallah and his Iranian masters have suffered a military blow and need time to rearm and regain political stature among their southern Lebanese supporters. As they pocket Mr. Annan’s gifts, they appear to be abiding by the rules.

Israel’s situation is much trickier. The most significant gain it made in the war was the recognition by most major players that leaving intact an unaccountable, heavily armed Hezbollah army is not sustainable. That consensus, however, is fast disappearing, along with the hope that Hezbollah will disarm soon.

As prominent international leaders arrive in Jerusalem daily like hospital visitors to an ailing relative, Israelis know they have not yet become the darling of the “international community.” When the annual U.N. General Assembly gets under way next week, new resolutions will condemn them in harsher tones than ever.

World leaders pledged billions in aid last week to rebuild Lebanon. If Israel’s U.N. gamble fails, a much more complex project will be required to rebuild the regional military hegemony the Jewish state needs to survive.