Following US strikes on Iran’s nuclear facilities, Russian official Dmitry Medvedev hinted that countries like Russia or North Korea might supply Iran with nuclear warheads directly. This threat should be met with a firm US response based on strategic brinksmanship. If Russia or its allies provide nuclear weapons to Iran, a state that has serially violated the Non-Proliferation Treaty, President Trump should make it clear that the United States will, in turn, provide nuclear weapons or station intermediate-range nuclear missiles in Russia’s own neighboring countries, such as Ukraine, Poland, or Kazakhstan, to re-establish deterrence.