The US did not agree to protect them. The signatures to the Budapest Memorandum agreed to respect Ukraine's sovereignty. Of the signatories, Russia is the only one that has violated the agreement.
Are you sure about that? Wikipedia says the following: "
3. Refrain from economic coercion designed to subordinate to their own interest the exercise by Ukraine, the Republic of Belarus, and Kazakhstan of the rights inherent in its sovereignty and thus to secure advantages of any kind.
4. Seek immediate Security Council action to provide assistance to the signatory if they "should become a victim of an act of aggression or an object of a threat of aggression in which nuclear weapons are used".
Both seems to not happen as stipulated.
Edit: I didn't read properly, 4 obviously didn't happen, my bad.
The actual memorandum is shorter than the Wikipedia article about it. The English-language portion is literally only three pages of double spaced text.
I guess you could argue the US is kinda violating 3, since I think the Trump administration tried to ask for future financial reparations in exchange for support during the war. But 4? This isn't a nuclear conflict yet right?
> 3. The United States of America, the Russian Federation, and the United Kingdom of Great Britain and Northern Ireland, reaffirm their commitment to Ukraine, in accordance with the principles of the CSCE Final Act, to refrain from economic coercion designed to subordinate to their own interest the exercise by the Republic of Belarus of the rights inherent in its sovereignty and thus to secure advantages of any kind.
I don't see how this qualifies. Being given weapons isn't part of sovereignty, and putting conditions on the continued flow of weapons isn't a violation of it.
Economic coercion attempting to violate sovereignty would be something like the threatened (actual?) tariffs on Brazil for imprisoning Bolsonaro.
