It has been almost a year since Russia and Iran signed their comprehensive strategic partnership. That deal established a 20-year partnership between the two countries covering the full spectrum of their relationship from military to economic to cyber ties. Though the two countries have cooperated deeply, from mass production of military drones to smuggling millions of barrels of oil, Russia did not come to Iran's aid when Iran endured 12 days of punishing war at the hands of Israel and the United States. Despite this, cooperation between Russia and Iran has continued. In November, Financial Times reported that Iranian scientists and nuclear experts made a second covert visit to Russia last year in what the United States claims has been a push to obtain sensitive technologies with potential nuclear weapon applications. Cooperation between the two remains a significant challenge for the United States and its allies.  

Hanna Notte is the director for Eurasia at the James Martin Center for Non-Proliferation Studies and a senior associate at the Center for Strategic and International Studies.

Nicole Grajewski is a fellow at the Carnegie Endowment for International Peace, an associate researcher at Harvard’s Belfer Center, and the author of Russia and Iran: Partners in Defiance from Syria to Ukraine.