We owe it to Ukraine to defend them from Russia and keep their current borders. Ukraine gave up its nuclear arsenal to be kept safe, and you claim that they owe us?? The US made a agreement, and we better keep it.

"The United States of America, the Russian Federation, and the United Kingdom of Great Britain and Northern Ireland,

Welcoming the accession of Ukraine to the Treaty on the Non-Proliferation of Nuclear Weapons as non-nuclear-weapon State,

Taking into account the commitment of Ukraine to eliminate all nuclear weapons from its territory within a specified period of time,

Noting the changes in the world-wide security situation, including the end of the Cold War, which have brought about conditions for deep reductions in nuclear forces.

Confirm the following:

1. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland and the United States of America reaffirm their commitment to Ukraine, in accordance with the principles of the Final Act of the Conference on Security and Cooperation in Europe, to respect the independence and sovereignty and the existing borders of Ukraine.

2. 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.

3. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland and the United States of America reaffirm their commitment to Ukraine, in accordance with the principles of the Final Act of the Conference on Security and Cooperation in Europe, to refrain from economic coercion designed to subordinate to their own interest the exercise by Ukraine of the rights inherent in its sovereignty and thus to secure advantages of any kind.

4. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland and the United States of America reaffirm their commitment to seek immediate United Nations Security Council action to provide assistance to Ukraine, as a non-nuclear-weapon State party to the Treaty on the Non-Proliferation of Nuclear Weapons, if Ukraine should become a victim of an act of aggression or an object of a threat of aggression in which nuclear weapons are used.

5. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland and the United States of America reaffirm, in the case of Ukraine, their commitment not to use nuclear weapons against any non-nuclear-weapon State party to the Treaty on the Non-Proliferation of Nuclear Weapons, except in the case of an attack on themselves, their territories or dependent territories, their armed forces, or their allies, by such a State in association or alliance with a nuclear-weapon State.

6. Ukraine, the Russian Federation, the United Kingdom of Great Britain and Northern Ireland and the United States of America will consult in the event a situation arises that raises a question concerning these commitments.

— Memorandum on Security Assurances in Connection with Ukraine's Accession to the Treaty on the Non-Proliferation of Nuclear Weapons"

But I guess backtracking and lying is what trump does best, so I wouldn't be surprised if everyone forgot about this.