We already did under the Budapest Memorandum on Security Assurances. Now we need to keep our word.
That's erroneous, at best.
The Budapest Memorandum was never even submitted to the US Senate for ratification as a treaty...in fact it was universally criticized as "a bridge too far".
It ws a BS letter signed by Bill Clinton without any other institutional backing or support.
In fact, even the Russians didn't submit for ratification to the Duma.