You must be a foreigner since you use NPR as a source, and you believe Bill Clinton was trustworthy. One more time, a treaty must be submitted to the US Senate and passed with a two-thirds majority before it has any force. It is nothing more than another worthless Bill Clinton promise.
You don’t like NPR? That information is all over the place. Here it is in Wikipedia.
https://en.wikipedia.org/wiki/Budapest_Memorandum
Ukraine gave up its nuclear weapons to Russia in exchange for a promise that Russia would not invade. US involvement in brokering the deal is incidental and the US Senate is irrelevant.
BTW, born in the US in 1957 and lived through the Cold War including cowering under my school desk during “duck and cover” drills. What’s less expensive? Stopping Putin now or the start of a new nuclear arms race?