If you remember the Cuban Missile Crisis it was in part over the fact that we have medium range missiles in Italy and Turkey, which just happened to be near the border of the Iron Curtain. We have long had the policy that we can do whatever we want in Europe but no one can dare enter the western hemisphere without our approval.
“no one can dare enter the western hemisphere without our approval.”
Which is called the Monroe Doctrine.
As to Russia if they were to decide to end this war and act like a civilized nation then they’d not have to worry about NATO. At one time they were actually on path to joining NATO but that all ended with Pootin.