Proliferation concerns have generally been associated with the acquisition of the fissile material needed for nuclear weapons; however, the spread of the knowledge needed to build very light and powerful weapons that can be carried long distances by missiles is also a serious concern. Such knowledge could accelerate and destabilize regional arms races, and lead to the deployment of powerful weapons able to target the US and its allies. Classified weapons-related information has previously spread through the international effort to harness inertial confinement fusion. Success in achieving net fusion gain in the National Ignition Facility at the Lawrence Livermore National Laboratory could lead to greatly increased R&D in inertial confinement fusion worldwide, along with increased proliferation risks. The authors write that these issues have not yet been adequately addressed and require direct and transparent examination so that means to mitigate risks can be assessed and residual risks can be balanced against potential benefits.