Most U.S. policymakers support critical U.S. investments in improving security to prevent the theft of nuclear weapons and weapons usable material in Russia. A few, however, are starting to raise doubts about whether this cooperation is a good idea. Skeptics argue that, because of Russia’s incursion into Ukraine, the federal government needs to make a stronger case for nuclear security cooperation with Russia. They argue that the U.S. case needs to address issues like the cost of nuclear security programs, the fungibility of money given to Russia for security upgrades, and the marginal benefit of nuclear security spending in Russia. The problem with these concerns is that they do not acknowledge the purpose of nuclear security cooperation: reducing the threat of nuclear terrorism.