Exactly. It is not our monkey. We don’t know enough about it to intervene one way or another.
I would disagree on that. Ukraine gave away world's third largest stockpile of nuclear weapons some ~20 years ago. Here is the gist of the assurances given to Ukraine for that.
http://en.wikipedia.org/wiki/Budapest_Memorandum_on_Security_Assurances#Content
According to the memorandum, Russia, the U.S., and the UK confirmed, in recognition of Ukraine becoming party to the Treaty on the Non-Proliferation of Nuclear Weapons and in effect abandoning its nuclear arsenal to Russia, that they would:
It is well known that treaties with Russia are not worth the paper they are printed on, but there were also USA and UK as parties. Now that Ukraine gave away their nuclear weapons and 20 years later Russia invaded and took parts from their country it will be certainly harder to convince other countries to keep away from having these weapons.