Of the U.S., Tonga or Canada, the one that never signed the Comprehensive Nuclear Test Ban Treaty
.... Canada, 000000001963-08-08-0000
Aug 8, 1963 (L, M, W) ..... Tonga, 000000001971-06-22-0000Jun 22, 1971 (M) [DOC] [TLE] Limited Test Ban Treaty - US Department of State [PAR] Signed at Moscow August 5, 1963 ...