As the U.S.-led coalition began its air campaign in Syria on Sept. 22, Israel Defense Forces (IDF) used a Patriot surface-to-air missile to shoot down a Syrian regime Su-24 aircraft after it strayed across the Israeli border. The incident normally would mean little, but its coincidental timing alongside the start of the coalition air campaign could allow rhetoric and perceptions to be shaped in a way that implies Israel is involved with the U.S.-Arab coalition's operation. As the coalition is already fragile by the nature of its design, this could complicate further cooperation between the United States and its Arab partners in the future.

The fact that the Syrian Su-24 strayed across the border is not surprising. The speed at which aircraft operate coupled with the Syrian rebels' position on the border at Quneitra would mean that any slight error in the pilot's angle of attack could unintentionally cause the aircraft to cross the border. IDF has vigorously defended its borders against Syrian forces that either stray or fire into Israel, and it ultimately holds the Syrian regime responsible for all security incidents that occur along the two countries' de facto border. Today's incident, however, marks the first time a Syrian aircraft has been shot down, but Damascus is unlikely to respond kinetically. Israel has launched attacks into Syrian territory throughout the civil war, and the government has been unwilling to respond because it cannot afford to tangle with a more advanced adversary while it is already engaged in an existential fight with rebels on the ground.

One complication that could arise from this incident is a shift in the official Syrian stance toward current coalition efforts. The coalition's ability to conduct widespread airstrikes throughout Syria has been enabled through de-confliction with Damascus and through its air defense assets. If tension grows between Syria and Israel — a major U.S. ally — it could lead Damascus to be less willing to allow air space access in future operations.

The situation is in many ways similar to the dynamic seen during the first war with Iraq, in which a U.S. coalition involving Arab members made it necessary for Israel to sit on the sidelines. Rhetorically, these Arab states do not want it even hinted that they are fighting fellow Arabs by Israel's side. In reality, such insinuations do not match the situation, but the timing of Israel's action could prompt accusations otherwise. This could be disruptive to the coalition if Arab populations back home latch onto the rumor. As of yet, nothing definitive has resulted from this incident, but the complicated dynamics shaping the entire operation make the U.S.-led coalition fragile. Any disruption, no matter how tangential, could severely restrict the scope and effectiveness of the campaign against the Islamic State.