How has the United States behaved historically toward friendly states with nuclear weapons ambitions? Recent scholarship has demonstrated the great lengths to which the United States went to prevent Taiwan, South Korea, and West Germany from acquiring nuclear weapons. Yet seemingly on the other side of the ledger are cases such as Israel, South Africa, and Pakistan, where the United States failed to prevent proliferation, and where many have argued that the United States made exceptions to its nonproliferation objectives given conflicting geopolitical goals. A reexamination of the history of U.S. nonproliferation policy toward Israel, South Africa, and Pakistan, based on declassified documents and interviews, finds that these cases are not as exceptional as is commonly understood. In each case, the United States sought to prevent these states from acquiring nuclear weapons, despite geopolitical constraints. Moreover, once U.S. policymakers realized that prior efforts had failed, they continued to pursue nonproliferation objectives, brokering deals to prevent nuclear tests, public declaration of capabilities, weaponization, or transfer of nuclear materials to other states.