I will never stop quoting this:

The dean of America’s Russia experts, George F. Kennan, had called the expansion of NATO into Central Europe “the most fateful error of American policy in the entire post-Cold War era.” Kennan, the architect of America’s post-World War II strategy of containment of the Soviet Union, believed, as did most other Russia experts in the United States, that expanding NATO would damage beyond repair U.S. efforts to transform Russia from enemy to partner.

The man who literally planned the containment of the USSR was adamantly against pursuing the same strategy against Russia. He died long before the toxic fruit of the strategy he warned against appeared and yet people just dismiss all that, like it never happened.