After the fall of the Berlin Wall, the West told Russia NATO would not expand eastward of Berlin. Since then, NATO added 14 countries east of Berlin. No legal agreements for NATO’s eastward expansions were made, but Russia’s concern is more than mere NATO membership. NATO countries are equipped with U.S. military bases pointing missiles at Russia. As of July of 2021, there are roughly 750 U.S. military bases in 80 countries, compared to Russia’s mere 21 overseas military facilities, leaving Russia paranoid about the West.
History shows us what would happen if Russia made an alliance with Canada or Mexico, putting military bases on our border with missiles aimed at the U.S. In January 1917, Germany sent the “Zimmermann Telegram” to Mexico revealing a plan for Germany to form an alliance with our southern neighbor, promising Mexico her lost territories of Texas, New Mexico and Arizona. This threat at our doorstep was one of the factors leading the U.S. to declare war against Germany five weeks later.
Also, you have to remember the Cuban Missile Crisis where nuclear war almost occurred over Soviet missiles in Cuba.
