Gonna be sad when NATO invokes Article 5 and the US refuses; considering the only time Article 5 has been invoked was by us and everyone answered the call.
So a NATO member chooses to jump into the middle of an active conflict between two Non-NATO nations and that somehow obligates us to get involved in the fight? Really? Are you sure?
Regardless, why would it be sad that we don't send people to die for some bombed out land in Ukraine that won't matter to the United States who owns it one way or the other? You would be sad?