If it didn't get approved by the US Senate (and, hint hint, the Budapest Memorandum didn't) then the treaty is not binding on the US. Other countries need to stop taking anything the US says or promises in international relations seriously until it goes through the senate. And admittedly, the US needs to stop making promises until it's sure it has the needed votes in the senate first.

You mean the treaty where Russia promised not to invade Ukraine?

AFAIK it was not international treaty, just political agreement not ratified by signing countries.