It is a weirdly common misconception that the agreement in question requires the US and UK to <i>protect</i> Ukraine&#x27;s territorial integrity. All it does is require them to <i>respect</i> it. This is the actual wording, taken from your link:<p>&quot;The Russian Federation, the United Kingdom of Great Britain and Northern Ireland and the United States of America reaffirm their obligation to refrain from the threat or use of force against the territorial integrity or political independence of Ukraine, and that none of their weapons will ever be used against Ukraine except in self-defence or otherwise in accordance with the Charter of the United Nations.&quot;<p>Basically, everybody involved pledged not to attack Ukraine. They made no pledge to protect Ukraine from other attackers. The only signatory who has violated the agreement here is Russia. The agreement does not require the US or the UK to protect Ukraine from Russia.<p>(Strictly speaking they are required to ask the UN to defend Ukraine if they are attacked or threatened by nuclear weapons, but that hasn&#x27;t happened.)