Question

a president has signed an arms control treaty approved by the Senate, but 20 years later, a different president thinks the terms are not stringent enough. what, if anything, can the new president do to change the situation?

Answer 1

Article II, Section 2 of the Constitution declares that the president "shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur." But it doesn't say anything about the power to break treaties.