Probably the only phrase that Ronald Reagan ever learned in Russian. He repeated the phrase "doveryai, no proveryai" at every opportunity during his 1987 arms reduction talks with Mikhail Gorbachev.

The phrase later became the motto of the Intermediate-Range Nuclear Forces (INF) inspection teams, which, between 1987 and 2001, made sure that the U.S. and the former Soviet Union were complying with the terms of the December 8, 1987 Intermediate-Range Nuclear Forces Treaty.

The idea is essentially the same as "good fences make good neighbors," and the phrase is repeated in diplomatic and business contexts to this day.