Ukraine and Iran will make Syria harder
Ukraine may seem far from Syria. But it is not. Nor is Iran. What happens in Ukraine won’t stay in Ukraine. What happens in Iran as well as Ukraine will affect the now more than decade-old war in Syria, through geography, markets, diplomacy, and politics.
The fighting and sanctions will hamper Russia in Syria
The Russians have been fighting insurgency in Syria since 2015, primarily with air power but also with some troops on the ground. The effort is not large, but Ukraine will take priority. Sanctions will severely limit Russian financial resources. This could affect not only military resources but also willingness to invest in reconstruction. The state-owned companies that might take such a risk are not going to have the cash to do it.
In addition, Russian relations with Turkey, the US, and possibly Israel will be strained. Cooperation with Turkey is important in northwest Syria, where Turkish troops and proxies are in control. Cooperation is important with the US in northeast Syria, where American troops are supporting the Kurdish-led Syrian Democratic Forces. Israel depends on Russian restraint when its aircraft attack Iranian forces and shipments inside Syria.
Moscow will have little reason to segregate the diplomatic and deconfliction issues in Syria from Ukraine. A weakened Russia may well seek pressure points in Syria to respond to international pressure in Ukraine.
Iran will be emboldened
Russia and Iran both support the Assad regime in Syria, but they also compete for influence there. Assuming the Iran nuclear deal revives, Tehran will have a lot more money with oil at around $100/barrel. Some portion of that will find its way to military and financial support for Assad. Even if the JCPOA remains moribund, Iran will find itself strengthened in Syria relative to Russia. It will try to use that strength to embed itself more strongly into the Syrian regime, in particular its security forces (which have grown closer to Russia in recent years).
An emboldened Iran will be less likely to compromise on Syria issues than a weakened Russia, but Moscow has the vital veto in the UN Security Council. Tehran might be even more inclined than Russia to shut off vital cross-border humanitarian assistance to Syrians, but in the end Moscow will decide.
The West’s stake in Syria will increase
The Ukraine war increases the West’s stake in Syria. Abandoning its anti-regime fight there would raise serious doubts about American and European resolve to continue support for Ukraine. Credibility isn’t everything, but it is something. The Biden administration had already tacitly recommitted the US to its continuing presence in northeast Syria supporting the Kurds and allied Arabs, if only to avoid a second Afghanistan debacle and to continue the counter-terrorism fight.
Net net
Syria has not been going anywhere anyway. The UN-sponsored constitutional talks are stalled, humanitarian relief is falling short, terrorism threats are growing, and accountability for war crimes and crimes against humanity is limited for now to gathering of documentation and the German courts. Russian weakness, Iranian strength, and Western resolve are going to make things harder, not easier.