Since the mid-1990s, much has been written about the potentially disruptive impact of China if it emerges as a peer competitor challenging the United States. Not enough attention has been paid, however, to a more immediate danger—that the United States and a weaker China will find themselves locked in a crisis that could escalate to open military conflict. The long-term prospect for a new great power rivalry ultimately rests on uncertain forecasts about big shifts in national capabilities and debatable claims about the motivations of the two countries. By contrast, the danger of crisis instability involving these two nuclear-armed states is a tangible near-term concern. An analysis that examines the current state of U.S.-China relations and compares it with key aspects of U.S.-Soviet relations during the Cold War indicates that a serious Sino-American crisis may be more likely and more dangerous than expected. The capabilities each side possesses, and specific features of the most likely scenarios for U.S.-China crises, suggest reasons to worry that escalation pressures will exist and that they will be highest early in a crisis, compressing the time frame for diplomacy to avert military conflict.