Earlier quoted context omitted.
> Ukraine is not a member of NATO, so options are somewhat limited Ukraine not being in NATO means we aren’t obligated to intervene. We regularly intervene in various things without a treaty requiring it.
Absolutely. But if a NATO member is attacked, then member states are obligated to come to the member's aid. It's essentially tantamount to saying, if you are at war with a NATO member, you are at war with the whole bloc, which includes USA, UK, France (somewhat in/out member over the decades), Germany, Turkey, and so on. It's a formidable group that acts as a deterrent to any would-be aggressor. The US is not obligat…
In the end, there is no supranational tribunal for military allegiances - in matters of conflict, Hobbes' jungle is still very much there.