noun
containment policy
A political strategy aimed at preventing the expansion of a hostile power or ideology, often associated with Cold War-era U.S. policy toward the Soviet Union.
冷戦時代、アメリカはソ連に対して封じ込め政策をとった。
During the Cold War, the United States adopted a containment policy toward the Soviet Union.
封じ込め is the general noun meaning 'containment' or 'locking in', while 封じ込め政策 specifically refers to the political strategy.
Compound of 封じ込め (containment, from 封じる 'to seal' + 込める 'to put in') and 政策 (policy).