Yes. And the US is not obligated to do anything about that, and they indeed are not doing anything about it.
Thus such agreements have become worthless.
Had the US said five days ago, "we will use our military to ensure the Budapest Memorandum is followed", and defended Ukraine when invaded, then in the future if a similar agreement was proposed the country would trust that it would be followed. They did not, and this means that no one will again enter into a similar agreement.
I'm not claiming that a US military intervention would be the "correct" thing to do, merely that it would be necessary to preserve worldwide trust in treaties similar to the Budapest Memorandum.
It's not obvious to me that it's a recipe for peace and stability if every international agreement comes with an implicit "also we promise to invade everyone who doesn't comply" rider.
The enforcement here would presumably look like sanctions, plus materially coming to Ukraine's defense to expel the Russian invasion. I don't think anyone would seriously suggest that a counter-invasion of Russia itself would be a good idea.
Thus such agreements have become worthless.
Had the US said five days ago, "we will use our military to ensure the Budapest Memorandum is followed", and defended Ukraine when invaded, then in the future if a similar agreement was proposed the country would trust that it would be followed. They did not, and this means that no one will again enter into a similar agreement.
I'm not claiming that a US military intervention would be the "correct" thing to do, merely that it would be necessary to preserve worldwide trust in treaties similar to the Budapest Memorandum.