On the recordMay 21, 2003
Let me tell you this: The original moratorium said: The Secretaries of Energy and Defense may not initiate research and development leading to the production of a low-yield nuclear weapon. We have replaced the term ``research and development'' with the development definition ``development engineering'' leading to the production of a nuclear weapon. Essentially, what we have done, Mr. Chairman, is we have taken the existing ban, which the DOE says restricts their efforts to do any meaningful research, and simply said do the research.
Source
govinfo.gov
