Israel’s Legal Options to Deal with Syria

The overthrow of Syrian dictator Bashar al-Assad in December created a dangerous power vacuum. Actions to fill this void were attempted by Assad loyalists, competing Syrian terrorist groups, Russia, Turkey, and Israel. The range of possibilities for Syria’s future is so broad, from hopeful to tragic, that its relationship with Israel may approach either of two extremes under international law.

Most of Syria has fallen under the control of the Sunni terrorist group Hay’at Tahrir al-Sham (HTS). HTS forged a well-deserved reputation of hostility toward Israel, as well as the Israel-friendly Druze community, which straddles the Israeli-Syrian border. HTS’s military momentum enabled its jihadis to start killing Syrian Druze and violently capture the two Syrian provinces on Israel’s border. In response, the Israeli Defense Force (IDF) sprang into action. The IDF staked out a strip of southwest Syria long known as an Israeli-Syrian demilitarized zone, launched a series of air strikes on Assad’s abandoned military assets to keep them from terrorist hands, and used airpower to defend the Druze population.

Earlier this month, President Trump visited the region with his own agenda. Among other things, he met with HTS strongman and former al-Qaeda captain Ahmed al-Sharaa. The president told the Islamist leader that the US would drop all anti-terrorism sanctions against him, HTS, and Syria. He also encouraged al-Sharaa to normalize relations with Israel.

The UN secretary general and HTS have argued that the IDF mobilization to the demilitarized zone violated the Israeli-Syrian ceasefire agreement of 1974. In fact, Israel terminated that agreement at the outset of the IDF mission, rendering the demilitarized zone obsolete. The law is clear: a treaty may be terminated due to a “fundamental change of circumstances” such as the one occasioned by the fall of Assad.

The ceasefire termination legally reverted Israel and Syria to a state of war that began in 1948, when Syria and its allies first invaded Israel. Thus, Israel revived its right of military defense against Syria.

Against this backdrop, Israel may legally pursue either or both of two approaches: continue the IDF mission in Syria or negotiate a normalization deal with Syria’s new government.

Israel may lawfully keep its troops in Syria pursuant to the revived state of war. Even without the state of war, Israel could invoke its right of self-defense against HTS based on UN Charter Article 51 and customary international law. A state may use force in self-defense against an actual armed attack or in “anticipatory self-defense” of an imminent armed attack. The classic example of anticipatory self-defense is the 1967 Six-Day War, when the IDF preempted a joint invasion by Syria, Egypt, and Jordan. A legally similar event occurred in 2007, when Israel preemptively bombed Syria’s nuclear reactor.

The term “imminent armed attack” is not explicitly defined. However, in 2012 the US and other democracies formulated a set of criteria known as the Bethlehem Principles. Applying the criteria to the HTS-Israel face-off, Israel may validly consider an armed attack from HTS to be imminent.

The first criterion of the Bethlehem Principles examines the “nature and immediacy of the threat,” disregarding whether the defending state knows the exact time, place, and means of attack. The UN Security Council and all leading democracies designated HTS a terrorist organization. In a 2018 video, Mr. al-Sharaa pledged to conquer both “Damascus” and “Jerusalem.” Although al-Sharaa recently offered to normalize relations with Israel “under the right conditions,” he never stated the conditions. Instead, he threatened Israel’s territorial sovereignty by demanding that Israel withdraw from the Golan Heights, a Druze-majority area considered Israeli land by Israel and the US although recognized as Syrian territory by other countries. Consistent with the threat, HTS also captured the Syrian provinces that border the Golan. Elsewhere in Syria’s sectarian chaos, Hezbollah and ISIS remain active. Both terror groups have killed Israelis and vowed to destroy Israel.

The next Bethlehem criterion considers whether any third parties support the anticipated aggressors. HTS’ main backer is Turkey, a major military power that reviles Israel. Operatives in Turkey transfer millions of dollars from Iran to Hamas, one of the Iranian terrorist proxies currently at war with Israel. Turkey already controls much of northern Syria and is now negotiating a defense agreement with HTS. Equally ominous, Turkey has authorized the installation of military positions in Syria for Hamas. Turkey’s Islamist leader marked the end of this year’s Ramadan by praying for Allah to destroy Israel. Notwithstanding these threats, Turkey and Israel have recently reached an agreement in principle to avoid military clashes, though each side’s freedom of action remains unclear.

The Bethlehem analysis also asks whether the anticipated attack is part of “a pattern of continuing armed activity.” The anticipated HTS attack would further the war on Israel started by Arab powers in 1948, continued by Iran and its terror proxies in this century, and now intensified by Turkey.

Another Bethlehem factor estimates the scale of potential damage from the anticipated attack. Syrian-based extremists could invade Israel and replicate Hamas’ antisemitic massacre of October 7, 2023. Even more fatalities may result if the invaders can snatch leftover weapons from the Assad regime. Some of those assets include chemical weapons facilities. With assistance from Turkey, which boasts 800,000 ground troops, American-made fighter jets, and a world-class navy, the feared assault could metastasize into a genocidal war against Israel.

Finally, the Bethlehem standard calls for an inquiry into less drastic alternatives to the defensive use of force. In this case, Israel and HTS have discussed ways to normalize relations but have not announced an agreement. Terrorist groups are hardly known for their willingness to compromise. And the UN peacekeeping force assigned to maintain the Israeli-Syrian ceasefire has not so much as admonished the HTS killers.

In sum, Israel has a strong right of anticipatory self-defense against HTS. Whether the right will extend to other Syrian terror cells depends on how they navigate Syria’s current state of anarchy.

The more hopeful possibility is that the Syrian-Israeli talks will produce a normalization agreement resembling the Arab-Israeli Abraham Accords. Such an arrangement could be historic in scope. In a best-case scenario, the two nations would replace their 77-year state of war with a peace treaty that includes a pledge of mutual sovereign recognition and a resolution of their border dispute.

Beyond that, the parties could sign a “status of forces” agreement to prevent military conflicts. For example, Mr. al-Sharaa could permit the IDF to use unmanned military monitoring stations and aerial monitoring in southern Syria, instead of its existing troop presence, to guard against terrorist threats. The parties could also commence diplomatic relations, permit a degree of autonomy for the Syrian Druze, build trade ties, and even form a defense pact against Hezbollah and ISIS, their mutual enemies.

Of course, any contract of peaceful co-existence between Syria and Israel would require HTS to transform itself from an Islamist terrorist group to a responsible government. To that end, HTS would need to guarantee the cooperation of its rank-and-file militants, as well as Russia and Turkey. The agreement would preferably be structured so HTS does not receive its expected benefits until it diffuses the terror threat against Israel. And Israel must prepare a convincing response to any Syrian demand for ownership of the Golan. These are tall orders. But if implemented, the efforts could finally bring stability to a highly unstable part of the world.