"The United States maintains more than twenty times the number of nuclear warheads that China does (1,350 compared to 45 deployed and 4,000 compared to 270 when including stockpiles, according to the Arms Control Association). This reflects Washington's more aggressive nuclear posture, which holds that the U.S. has the right to launch a nuclear first strike in a conflict, even if it has only been attacked with conventional weapons. (Moscow has a similar stance, claiming it may use tactical nuclear weapons to ‘de-escalate' a conventional war.) China, by contrast, has a defensive nuclear doctrine claiming it will only employ nukes if attacked with them first."
