Many strategists argue that to deter a nuclear attack, states must be certain of their ability to retaliate after a nuclear first strike. China's nuclear posture of uncertain retaliation suggests an alternative logic. Given the catastrophic consequences of a nuclear attack, uncertain retaliation can have a strong deterrent effect, and assured retaliation is not necessary. A simplified nuclear exchange model developed to evaluate China's nuclear retaliatory capabilities against the Soviet Union in 1984 and the United States in 2000 and 2010 shows that China's nuclear retaliatory capability has been and remains far from assured. In its 2010 Nuclear Posture Review Report, the United States promised to maintain strategic stability with China; therefore, the 2010 scenario can be considered as a baseline for China-U.S. strategic stability. Both China and the United States are developing or modernizing their strategic offensive and defensive weapons. The technical competition between China and the United States favors each in different ways. A hypothetical scenario of China versus the United States in 2025 reveals that China-U.S. strategic stability will likely be maintained at no lower than its 2010 level.