Especially when it violates a treaty you signed promising that if the country you invaded disarms itself that you would protect it.

You missed the part where USA baked the second coup in that country in a decade and put in power people, that were intended to kick Russian army and fleet away from Crimea bases.

Okay, and compared to the myriad of other problems the world has right now and the US has right now. . .how is it our problem and what do you suggest we do about it?

Should we nuke them? Surely not?

Let Europe handle her political disagreements. We have no place there. The present breathless escalation of tensions only leads to one place and it's not good at all.

Why is the United States taking the lead at all in a conflict between countries with a history of conflict longer than the US has been around? European powers routinely engage financially with Russia in the form of pipeline contracts, friendly coordination on multiple other areas such as environmental protection etc.

This is all just a proxy fight for the natural resources (Oil) in Crimea and Ukraine and that's disgusting.