John Kerry met illegally with the North Vietnamese communists in 1970, in direct violation of US law.
U.S. code 18 U.S.C. 953 “A U.S. citizen cannot go abroad and negotiate with a foreign power”
Later he met illegally with another communist dictator in Nicaragua
Now he is angry that the US Senate is asserting the Constitution.
[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