On January 17, 1967, Thurmond was appointed to the Senate Judiciary subcommittee on Constitutional Rights. In March, as the Senate passed an endorsement of the United States antiballistic missile system, Thurmond engaged in a back and forth with Joseph Clark after Clark mentioned that Charleston, South Carolina would be included in the Pentagon's list of twenty-five American cities that would get priority in their antimissile protection and attributed this to the influence of Chairman of the House Armed Services Committee L. Mendel Rivers. Thurmond then demanded a rule that would bar senators from being able to disparage members of the House of Representatives in addition to preventing them from speaking and having to remain seated. Clark argued that the rule did not apply to him since he had finished speaking, Thurmond rebutting, "If the senator is not going to be man enough to take his medicine, then let him go." Thurmond then won unanimous approval to have Clark's remarks removed from the record. In July, after the 1967 USS "Forrestal" fire, Thurmond wrote of his conviction that the outbreak had been precipitated by communists. In September, Thurmond warned against enacting any of the three proposed Panama Canal treaties, which he said could lead to Communist control of the waterway if enacted.