While Turkey has given quiet support to various forces opposed to Bashar al-Assad since the civil war broke out in Syria in 2011, last week was the first time Turkish and Syrian troops fought each other directly—with exchanges of fire leaving soldiers on both sides dead. Jonathan Spyer considers whether the confrontation between the two will escalate, and how Russia will respond:

It is undoubtedly the case that the Syrian regime’s attack on Turkish personnel is a blow to Russian diplomacy. Since emerging as the key diplomatic arbiter in Syria following its entrance into the conflict in September 2015, Russia has sought to maintain cordial relations with a variety of warring sides: Israel and Iran, Turkey and the [Kurdish] PKK militia, Turkey and the Syrian government.

[But the recent clashes] need not mean the general collapse of Russian mediation and diplomacy. Israel has killed Iranian personnel [in Syria] on numerous occasions during its air raids over the last three years, [despite the presence of] Russian air defenses . . . on Syrian soil. [Likewise], the Syrian Kurds have been severely let down by Moscow on a number of occasions, as a result of the Russian strategic goal of inducing Turkey away from its alliance with the United States.

Yet these undoubted Russian betrayals did not result in a wholesale turning away from Moscow on the part of either the Iranians or the Syrian Kurds. On the contrary, both these forces need their relationship with Russia to provide at least a part of what they want. Without the presence of Russia, Israel’s actions against Iran in Syria would likely be far more intense. Russia, meanwhile, prevented a catastrophic [Turkish attack on Kurds] on a larger scale.

Russia, because of the U.S. decision to avoid major engagement in the Syrian war, has emerged both as the decisive military factor and consequently as the main diplomatic force in the country. Since everyone needs it to get anything done, and since there is no alternative patron available, Moscow remains the indispensable partner for all.

Below, today’s newsletter will return to some other reflections on the one-year anniversary of the outbreak of the current war, but first something must be said of its recent progress. Israel has kept up its aerial and ground assault on Hizballah, and may have already killed the successor to Hassan Nasrallah, the longtime leader it eliminated less than two weeks ago. Matthew Levitt assesses the current state of the Lebanon-based terrorist group, which, in his view, is now “a shadow of its former self.” Indeed, he adds,

it is no exaggeration to say that the Hizballah of two weeks ago no longer exists. And since Hizballah was the backbone of Iran’s network of militant proxies, its so-called axis of resistance, Iran’s strategy of arming and deploying proxy groups throughout the region is suddenly at risk as well.

Hizballah’s attacks put increasing pressure on Israel, as intended, only that pressure did not lead Israelis to stop targeting Hamas so much as it chipped away at Israel’s fears about the cost of military action to address the military threats posed by Hizballah.

At the same time, Levitt explains, Hizballah still poses a serious threat, as it demonstrated last night when its missiles struck Haifa and Tiberias, injuring at least two people:

Hizballah still maintains an arsenal of rockets and a cadre of several thousand fighters. It will continue to pose potent military threats for Israel, Lebanon, and the wider region.

How will the group seek to avenge Nasrallah’s death amid these military setbacks? Hizballah is likely to resort to acts of international terrorism, which are overseen by one of the few elements of the group that has not yet lost key leaders.

But the true measure of whether the group will be able to reconstitute itself, even over many years, is whether Iran can restock Hizballah’s sophisticated arsenal. Tehran’s network of proxy groups—from Hizballah to Hamas to the Houthis—is only as dangerous as it is today because of Iran’s provision of weapons and money. Whatever Hizballah does next, Western governments must prioritize cutting off Tehran’s ability to arm and fund its proxies.