The US has no more business getting involved in the conflict between Russia and Ukraine than it would in the conflict between India and Pakistan, and NATO has even less reason to be involved.
NATO was formed in 1949 to protect Western Europe from invasion by the Soviet Union, which had the world's largest army at the end of WW2. The ensuing Cold War justified this alliance until the Soviet Union dissolved in 1991. After that the threat of International Communism ceased to exist, and Western Europe began cooperative relations with Russia. However the NATO military establishment maintained a hostile attitude towards Russia, and expanded into many of the Eastern European countries near Russia's border. When Ukraine became the next candidate for NATO expansion, Russia responded with military action to prevent this from happening. NATO countries (including the US) then responded with military assistance to Ukraine, even though it was not (yet) a NATO member.
NATO is now involved in an undeclared war with Russia, even though Russia has not invaded any NATO member. This fact further undermines the original purpose of NATO, and actually lessens the security of its European members. It also places the US in an unacceptable position of being drawn into conflicts which have no bearing on its own national security interests. The countries of Western Europe have economies many times that of Russia, and could easily defend themselves if they needed to. As a result, the US has no need or responsibility to defend them or become involved in extraneous foreign conflicts.
NATO was formed in 1949 to protect Western Europe from invasion by the Soviet Union, which had the world's largest army at the end of WW2. The ensuing Cold War justified this alliance until the Soviet Union dissolved in 1991. After that the threat of International Communism ceased to exist, and Western Europe began cooperative relations with Russia. However the NATO military establishment maintained a hostile attitude towards Russia, and expanded into many of the Eastern European countries near Russia's border. When Ukraine became the next candidate for NATO expansion, Russia responded with military action to prevent this from happening. NATO countries (including the US) then responded with military assistance to Ukraine, even though it was not (yet) a NATO member.
NATO is now involved in an undeclared war with Russia, even though Russia has not invaded any NATO member. This fact further undermines the original purpose of NATO, and actually lessens the security of its European members. It also places the US in an unacceptable position of being drawn into conflicts which have no bearing on its own national security interests. The countries of Western Europe have economies many times that of Russia, and could easily defend themselves if they needed to. As a result, the US has no need or responsibility to defend them or become involved in extraneous foreign conflicts.