This CRS Report discusses China’s suspected acquisition of U.S. nuclear weapon secrets, including that on the W88, the newest U.S. nuclear warhead, since the late 1970s. This current controversy, began in early 1999, raises policy issues about whether U.S. security is further threatened by the PRC’s suspected use of U.S. nuclear weapon secrets in its development of nuclear forces, as well as whether the Administration’s response to the security problems is effective or mishandled and whether it fairly used or abused its investigative and prosecuting authority.