I oppose US involvement.
It’s Europe’s problem.
I'm in partial agreement with you here.
1. We did make "security assurances" to Ukraine in that 1994 Budapest Memorandum to get them to give up their nukes. (Which was probably stupid in hindsight.)
The help we've given them up to this point I think fulfills our obligation - the U.S. gave our word, and we came through in helping Ukraine through a couple months of invasion.
2. Putin has outright said - as recently as the night before this ridiculous war - that he wants to re-establish the USSR. It is in American citizens' interests to make sure that doesn't happen.
But that second point goes for Europe 10X more that it goes for the USA. Those laggards in Europe need to wake up and start fulfilling their basic security obligations to their citizens, rather than making ours responsible.
If Russia takes Mariupol and Odessa they will control about 75% of the worlds production of Industrial NEON with China controlling most of the rest. Industrial NEON is required for laser etching microchips. It is very difficult to refine and a start up plant would take about a year to get up and running if you could even get a reliable source for harvesting the neon. Having Russia and China basically control the world’s production of microchips IS our problem.