What are the risks and opportunities for Russia as it grows closer to Iran at Israel's expense?

Russia's national security chief, Sergei Shoigu, traveled to Tehran this week where he met with Iran's new president, Masoud Pezeskhian. Coming on the heels of the killing of Hamas leader Ismail Haniyeh on Iranian soil, Shoigu's visit prompted a flurry of speculation about the Kremlin's intentions. Iran has vowed revenge for the attack which it has blamed on Israel. Hanna Notte, head of the Eurasia program at the James Martin Center for Nuclear Non Proliferation Studies, unpacks the stakes.