Development of the B61 11 has been controversial. Some critics have argued that it would undermine the Comprehensive Test Ban Treaty because it would be seen as a "new" weapon that was developed after the treaty's signature in September 1996. They contend that the B61 11 is a new weapon because it gives the United States a new capability¾to destroy deeply buried targets, such as command and control bunkers. The position of the U.S. government is that the B61 11 is only a modification of the existing B61 7 bomb and that it utilizes an existing nuclear package that has not required a nuclear test.
Some critics have also argued that development of the B61 11 may call into question U.S. "negative security assurances," whereby the United States has pledged not to use nuclear weapons against any non nuclear weapon state party to the nuclear Non Proliferation Treaty (NPT) unless attacked by such a state that is allied with a nuclear weapon state. Although subsequently repudiated, Harold Smith, assistant to the secretary of defense for nuclear, chemical and biological defense programs, asserted in April 1996 that the B61 11 could be used to destroy a suspected underground chemical weapons facility under construction in Libya, a member of the NPT.