Going beyond superficial comparisons of Kissinger and Brzezinski, this study determines their impact on US national security policy by comparing their views on world politics and on strategy and tactics for achieving national goals and by examining the consistency between their actions in office and their beliefs. Despite his attacks on Kissinger, this study found that Brzezinski shared many of Kissinger's beliefs and copied many of his actions in office. Both men's actions were profoundly shaped by their shared beliefs that, within limits, man could shape history, that Moscow's and Peking's commitment to worldwide communist expansion is the main threat to peace, and that divergent national interests threaten even allied relationships, and by their parallel conceptions of power, diplomacy, linkage, and leadership. Indeed, their similar struggles to control policy through the National Security Council and more informal structures and their handling of relations with allies, and with Moscow, and Peking underlined these shared beliefs, as well their differing conceptions of morality and leadership. Moreover, since leaving office, both Kissinger's and Brzezinski's policy proposals clearly restate their shared beliefs.