The President and many Americans would like for us to leave NATO because we don’t need to be involved with European defense. When Trump was asked if American boys should have to go fight in Montenegro, he said that is the problem with NATO rules. Article Three has only been invoked once and we did it after 9-11. It is why several NATO countries are still in Afghanistan.
We were isolationists before WWI and WWII. Since NATO, Europe has not had a war or much of a verbal disagreement. The Cold War was a uniting factor because Stalin had put his massive army in the Warsaw Pact countries. West Germany, Austria, Italy, Greece, and Turkey could feel his hot breath on them. When the Warsaw Pact dissolved, those countries asked to be in NATO to prevent Russia from pulling them back into Russia’s fold.
Today’s Russia is using its military to start getting parts of the pact back. The first was to cut off part of Georgia and nobody came to their aid because they weren’t in NATO. Next he hid his marines in ships anchored in the leased harbor in the Crimea. One night they flooded out and took control of the Ukraine’s Crimean Peninsula. The next year Putin sponsored an insurrection in Western Ukraine, supplied arms and finally “volunteers” with high tech weapons. It was a Russian missile operated by “volunteers” that shot down a KLM Airliner. Western Ukraine – another country not in NATO.
The Baltic countries of Lithuania, Latvia and Estonia asked and got NATO troops to be an additional tripwire because Putin is eyeing their countries now. We have at least a company in each country along with those from other NATO countries.
Putin wants those Warsaw Pact countries back even if he has to nibble of pieces of them year after year. NATO prevents Russia from doubling the size of the army and starting little wars, which could become big ones.
Commentary About the Blue Marble 
Ahhh…You forget or ignore Bosnia, Libya, and Syria.
I’m not against NATO per se, but they need to be reigned in more than bit, especially their attempts to add ex-Soviet nations to it.
Oh, and like it or not, Putin’s forces didn’t “take control” of the peninsula until after it’s residents voted to rejoin the Russian Federation, largely because they were either Russian by blood and culture or not White enough to fair well under the Nazi – used advisedly – regime coming into power.
Again, not a fan of Russia or Putiin, but let’s keep it real and also not instantly complain when Russia seeks to regain territory. After all, they’re not the “Communist Threat” anymore so we might want to leave some of the Cold War attitudes behind.