There is no such treaty, nor has such a treaty ever been presented to the United States Congress for ratification...Ukie propaganda to the contrary notwithstanding.
It's called the Budapest Memorandum. And just because it wasn't ratified by the US doesn't negate the fact that Russia signed off and agreed to it.
FIRST:
Budapest Memorandum reinforced obligations that all of the signatories had already legally agreed upon by signing the UN Charter!!!
SECOND:
BUDAPEST MEMORANDIUM NUCLEAR NON-PROLIFERATION TREATY (NPT): Is an international treaty shared now currently with 189 member states to limit the spread of nuclear weapons. The treaty has three main pillars: nonproliferation, disarmament, and the right to peacefully use nuclear technology.
THIRDLY:
The Memorandum promised signatories respect for the independence, sovereignty and the existing borders of Ukraine and refrain from the threat or use of force against the territorial integrity or political independence of Ukraine.
[BTW: Between 1946 and 1999, the United States completed nearly 16,000 international agreements. Only 912 of those agreements were treaties, submitted to the Senate for approval as outlined in Article II of the United States Constitution.
Since the Franklin Roosevelt presidency, only 6% of international accords have been completed as Article II treaties. Most of these executive agreements consist of congressional-executive agreements.]