Military aircraft against the sunset and Turkey flag. (Adobe stock / ecrow)

Israel has every reason to be worried about Turkey’s growing military presence in Syria. It also has every reason not to turn that concern into a war with Turkey.

That is the difficult balance behind Israel’s recent strike on Syria’s Abu al-Duhur airbase. Israeli intelligence reportedly indicated that Turkish officers had visited the facility in preparation for deploying radar, air-defense systems and perhaps eventually Turkish combat aircraft. Syria and Turkey dispute that account. But the larger issue is undeniable: Ankara is becoming increasingly involved in rebuilding and training Syria’s armed forces and expanding its influence in the country.

Israel cannot simply watch that happen without asking where Turkish involvement becomes an Israeli security threat.

Oct. 7 changed the answer to that question. Israel spent years tolerating the accumulation of hostile military capabilities around its borders while distinguishing between what its enemies possessed and what Israeli intelligence believed they intended to do with it. The consequences were catastrophic. Israel is entitled to conclude that certain capabilities cannot again be permitted to develop on the assumption that they will never be used.

But that lesson should not be stretched too far. Former Israeli ambassador Michael Oren argues that Turkey, Qatar and Pakistan are emerging as a new “Sunni Axis” replacing Iran and its network of proxies. There are reasons for concern. Turkish President Recep Tayyip Erdoğan has become increasingly hostile toward Israel, while Foreign Minister Hakan Fidan recently called Israel a “burden that humanity can no longer bear.” Ankara’s ambitions in Syria are substantial.

Still, Turkey is not Iran. It is a NATO member with a powerful conventional military, important relations with Washington and its own complicated regional interests. Nor is there yet evidence of a Turkish-led military network comparable to the system Iran spent decades constructing around Israel.

That distinction matters. Israel cannot realistically demand that Turkey have no military relationship with Syria. Turkish trainers helping rebuild the Syrian army may be objectionable but are not necessarily intolerable. Turkish political influence in Damascus is something Israel may have to live with.

Turkish combat aircraft, advanced air-defense batteries or radar systems positioned in Syria are different. They could threaten Israeli territory, interfere with Israeli operations against Hezbollah and other enemies, and fundamentally change Israel’s freedom of action in its immediate neighborhood. That is where the red line should be drawn.

The United States is now attempting to establish an Israeli-Turkish-Syrian deconfliction mechanism. Washington should use that process to turn an ambiguous confrontation into explicit rules: Turkey may have interests in Syria, but it cannot deploy capabilities there that directly threaten Israel or prevent Israel from defending itself. That would be more valuable than repeatedly bombing Syrian airfields — and considerably less dangerous.

Israel was right to demonstrate that it will not passively accept a potentially threatening military buildup on its border. But red lines work best when everyone understands precisely where they are.

The objective should not be to keep Turkey out of Syria. It should be to keep Turkey from turning Syria into a military front against Israel. That is a line Israel can defend — and one Washington should help enforce.