Do you feel the United States has an obligation to the Ukraine due to the Treaty on Non-Proliferation of Nuclear Weapon?

In 1994 the US, UK, Russia and Ukraine signed the Budapest Memorandum, in which the three powers offered assurances that they would respect Ukraine’s territorial integrity. 20 Years later we all watched the news as Russia annexed part of the Ukraine (Crimea) Are we sending a message to the rest of the world that we do not live up to our promises and their best bet is to arm themselves with nuclear capabilities?