The Sino-Soviet Treaty remained in effect until 1979, after which relations deteriorated due to de-Stalinization. In what year did the treaty effectively end?

• A. 1950
• B. 1964
• C. 1979
• D. 1989

Answer: (C)

The key idea here is that a treaty can linger on the books even after the partners stop acting like allies. The Sino-Soviet treaty started in 1950 as a mutual defense pact between the Soviet Union and the People's Republic of China. After de-Stalinization, the two countries grew apart ideologically and strategically. Practical cooperation dissolved through the 1960s and into the 1970s, with tensions and actions that made the alliance untenable. By 1979, the relationship had deteriorated so far that the treaty no longer guided policy or commitments in any meaningful way. That’s why 1979 is used to mark the end of the treaty’s practical effect. The other dates either mark when the treaty began or moments before the split fully took hold, not when its functioning ended.