On Wednesday, Hezbollah issued a deterrent threat to the United States, stating that the Lebanese-based militant group will attack US forces if the US crosses certain “red lines” in Syria. Several times over the last few months, the US has launched air strikes against pro-Assad forces, including elements of Hezbollah, that the US has accused of violating the “de-confliction zones” set up by the US and Russia. Despite both the US and Iran being opposed to ISIS–and to some degree cooperating against the Islamic State in Iraq–in Syria, the two states goals are at loggerheads, with the US fighting primarily against ISIS while Iran strives to support the beleaguered regime.
The problem lies in the de-confliction zone, which Iran seems to seeking to control in order to develop a corridor through Syria to Lebanon, through which it could supply Hezbollah with weapons. The US, prodded to some degree by Israel and its Sunni allies, all of whom fear the rise of Hezbollah and the expansion of Iranian influence in the region, has been punishing violations of the de-confliction zone as a way to push back against Iran and its proxy.
Both sides have much at stake. Hezbollah has invested a lot of blood and treasure into defending the Assad regime; in the aftermath of the ISIS attack in Tehran, Iran is likely looking to escalate the war against ISIS in Syria. The US, of course, sees Israel as one of its most vital allies and the successes of Hezbollah in Syria could embolden the group to try something against Israel. It’s also possible that the occasional Israeli airstrikes against Hezbollah (almost certainly designed to prevent certain weapons systems from being deployed in Lebanon) could lead to an “accidental” war or even convince Israel to attack Hezbollah before its arsenal grows even larger and more dangerous. To be sure, many analysts have commented on the growing likelihood of a war between Israel and Hezbollah (for example, here, here, and here).
All of this creates a dangerous situation for the US in Syria, especially in the presence of direct deterrent threat. Is the US willing to risk escalation to a direct conflict with Hezbollah to maintain support for a rag-tag bunch of Syrian rebels? The US, without question, has an immense qualitative edge in military capability, but Iran and Hezbollah arguably have more at stake.
If the US intends to continue its support for Syrian rebels and its policing of the de-confliction zone, it needs to quickly decide what its goals in Syria are and what price its willing to pay to achieve those goals. While then-candidate Trump routinely criticized President Obama for his lack of action in Syria, there has been in practice little change in either strategy or tactics, outside of an uptick in the number of bombs dropped. President Trump, so far, doesn’t seem to be any more willing to risk US ground troops or take significant action to oust Assad. If that’s still the case, the US would be unwise to escalate into direct conflict with Hezbollah. However, given the threat to Israel, Jordan, and Saudi Arabia, among others in the region, the US should respond to Hezbollah with “red lines” of its own about geographical limitations for the militia. Such a threat is likely to be seen as credible, particularly following President Trump’s air strikes against the Syrian regime in response to the use of chemical weapons.
This is a dangerous moment in Syria. There should be little confidence that President Trump is intelligent or nuanced enough to devise a smart strategy to contain Hezbollah and Iran as his insulting and ham-fisted “condolences” to Iran demonstrated. Only someone short-sighted would rub salt in the wounds of someone with whom is shared a large number of strategic interests and concerns; only someone stupid would do so in such a low-cost scenario as expressing sympathy after a brutal terror attack. The presence of Mattis and McMaster in the key national security positions provides some hope. The US needs to balance its unwillingness to become seriously involved in Syria with a need to reassure its regional allies, contain Iran, and prevent what would be a disastrous war between Israel and Hezbollah. That is a delicate balancing act. But now is the time to try. e US needs to respond clearly and effectively to Hezbollah’s deterrent threat and it needs to respond soon.