Former US ambassador to Russia Michael McFaul met Russian President Vladimir Putin in 1991. “At the time, if you had asked me to list 5,000 Russians that might be the next president of Russia, he would not have made this list. Now the man that Americans had disregarded is the key to restraining Iran in Syria and ensuring that tensions between Israel and Iran do not boil over. Why? Because Russia has invested heavily in the survival of its Syrian regime ally and hopes for stability in Syria.With Prime Minister Benjamin Netanyahu in Moscow for Victory Day celebrations, Russia now plays a key role after Washington withdrew from the Iran deal.Netanyahu planned his Moscow trip as Trump was deciding about leaving the deal, and it was not definitely clear that Trump’s speech would come a night before the trip.However, the Iran issue has always hung over Israel-Russia relations in the last years. Russia has successfully pursued several tracks in Syria in this regard.Putin has warm relations with Netanyahu, and Moscow considers Israel’s air raids in Syria part of its differences with Jerusalem. Russia, a key ally of Syrian President Basher Assad, increased its role in Syria in 2015.Criticism of Israel’s air raids by Moscow, which was very rare between 2015 and 2017, has increased. Russia also pursues a second track in Syria at the Astana peace talks alongside Iran and Turkey, discussing how to “de-escalate” the Syria conflict. Putin, Iranian President Hassan Rouhani and Turkish President Recep Tayyip Erdogan met in April of this year and in November 2017 to discuss Syria. Putin also concluded a cease-fire agreement in southern Syria in July 2017 with the US and Jordan.Unlike Trump, who has no relations with Iran and difficult relations with Turkey, Putin is now the key to Syria. Moscow’s main interest is what it calls “stability” in Syria. That means basically not entering into new conflicts with the US and its partners in eastern Syria, Jordan and the Syrian rebels in the south, or Turkey and the rebels in the north. It also means not having Iran and Israel fight a war in Syria.A conflict between Israel and Iran in Syria is the most likely outcome of any tensions between Jerusalem and Tehran. These tensions existed before Trump left the deal and will continue after.Over the next 180 days, Iran will watch as Washington decides which sanctions to reimpose. Already the Iranian economy is struggling, and the Iranian rial has reached record lows. Iran would view with caution any real war with Israel. But Iran has warned of retaliation for Israeli air strikes in Syria.Here, Moscow can play a constructive role because it speaks to both Jerusalem and Tehran. We don’t know the substance of what Netanyahu and Putin have said regarding this, but it’s clear that Jerusalem knows Russia is a key to calm in the north. Russia is also a key because of its air defenses in Syria. In contrast to the Trump administration’s goals in Syria, which have tacked from staying or going, Russia’s are clear.What is less clear, is which way Russia is trending on Iran’s role in Syria. Russian English-language media, Russia Today and Sputnik, highlight the tensions in Syria and give credence to reports by Syrian state media that Israel launched air strikes on Syria on May 8.In addition, Russia Today has a piece with a commentator saying that the Israel “lobby is calling the shots in Trump’s rollback policy on Iran.” This may not be indicative of Moscow’s overall thinking, but it certainly is an element of it.