Kissinger said you can bypass the constitution via the use of treaties.
Kissinger is not a lawyer, nor even an expert on US Constitutional Law. If he said it, he was mistaken. Numerous of the Founders including Madison and Jefferson commented on the meaning of the Supremacy Clause as it relates to treaties, and the Supreme Court has ruled on several occasions. The existing precedent is essentially that Treaties have the same standing as Federal Law: they are subservient to the Constitution.
The most recent precedent, by a pretty liberal court in 1957 was established in Reid v. Covert. Among many things written there which demolish the claim that a treaty overrides the Constitution, the Court wrote:
"This Court has regularly and uniformly recognized the supremacy of the Constitution over a treaty."