trust, but verify

Calque of Russian доверяй, но проверяй (doverjaj, no proverjaj). Often attributed to Vladimir Lenin, although no written evidence exists. Popularized in English by Ronald Reagan in the context of nuclear disarmament.

trust, but verify

1. You can only rely on things you verified yourself.
   • 2013, Kelly C Bourne, Application Administrators Handbook: Installing, Updating and Troubleshooting Software, Newnes (→ISBN), page 351:

     If I had blindly fulfilled her first request, it would have inconvenienced many other users and wouldn't have solved the problem. Never forget this phrase - “trust, but verify.”

   • 2014, David DeSteno, The Truth About Trust: How It Determines Success in Life, Love, Learning, and More, Penguin (→ISBN), page 97:

     Trust but verify—plain and simple. Well, mostly just verify, as the objective record removes the vulnerability of getting cheated.

• trust, but verify on Wikipedia.Wikipedia