The U.N. Security Council recently renewed the mandate of the U.N. Interim Force in Lebanon (UNIFIL), the international peacekeeping force that has been present in Lebanon since 1978. Under pressure from the United States, the Security Council charged U.N. Secretary General António Guterres with finding ways to “increase UNIFIL’s visible presence, including through patrols and inspections.” But this may fall short in helping UNIFIL carry out its mission.

UNIFIL’s original mandate was to ensure Israel’s withdrawal from Lebanese territory and the assertion of Lebanese authority throughout the country. After Hezbollah’s 2006 war with Israel, the U.N. expanded UNIFIL’s mandate to assist the Lebanese Armed Forces (LAF) in “taking steps” to ensure that southern Lebanon remains free of unauthorized weaponry and “armed personnel.”  

Nonetheless, thanks to its patron Iran, Hezbollah has grown into a regional military player. Middle East security officials have documented how Hezbollah has more than tripled the number and lethality of its rockets and other weaponry since the 2006 war. Hezbollah’s participation in the Syrian civil war for the past five years alongside the Syrian army has directly shifted the balance of power in that conflict. We most recently witnessed this with Hezbollah’s arrangement—in coordination with the Syrian government—for ISIS fighters to be bused from near the Lebanese border to areas under the terror group’s control in Syria’s east.

UNIFIL has consistently lacked the authority to directly confront Hezbollah. And the Lebanese army has proven unwilling or unable—or both—to disarm the terror group. During a press tour of Hezbollah’s positions in southern Lebanon earlier this year, for example, Hezbollah fighters openly showed reporters rocket-propelled grenades and other artillery. When an Italian UNIFIL officer reportedly tried to clear the group from a restricted area near an Israeli listening post, a Lebanese army officer instead escorted the UNIFIL officer away.

Contrary to the facts on the ground, UNIFIL has repeatedly claimed that it has not witnessed any Hezbollah weapons entering southern Lebanon. In 2008, Colonel Marc Ollier of the French UNIFIL contingent said that he didn’t “believe Hezbollah's weapons figure in Resolution 1701.” According to a U.N. spokeswoman earlier this year, “UNIFIL has not observed any unauthorized armed persons … or found any basis to report a violation of the (cease-fire) resolution.” UNIFIL issued a similar statement in 2015.

Ahead of the Security Council’s debate, Lebanon called on the U.N. to renew UNIFIL’s mandate but without any changes. U.S. Ambassador to the U.N. Nikki Haley sharply criticized UNIFIL for allowing Hezbollah to rebuild its arsenal in southern Lebanon. Haley further accused UNIFIL’s commander of being “blind to what Hezbollah is doing.”

Both Lebanon and the United States were reportedly satisfied with the outcome of the U.N. debate, but it is now up to Guterres to determine how much authority UNIFIL will have to confront Hezbollah and prevent it from growing even stronger. Unless UNIFIL’s teeth are sharpened, Hezbollah will continue its military expansion in Lebanon and Syria. And that will be bad for everyone—except Iran.