This past summer, the Lebanese Armed Forces (LAF) launched an offensive that made significant headway against Islamic State forces in northeast Lebanon. But its counterterrorism efforts have repeatedly run into interference from Hezbollah, which not only launched its own operation against al-Qa`ida-aligned militants in an apparent attempt to upstage the LAF but also undercut the LAF’s offensive against the Islamic State by helping to broker safe passage into Syria for a large number of Islamic State fighters. While the defeat and displacement of Sunni jihadis in Lebanon has improved the security outlook for Lebanon (though not Syria and Iraq), Hezbollah’s decision to enter the fray—borne out of concern the LAF might otherwise accrue prestige and strengthen its popular standing to the Iran-backed party’s detriment—risks raising tensions in Lebanon.