Iain Murray explains that the US treaty ratification process is a little more complicated than the rest of the world makes it out to be.
There are therefore two main differences between the American system and the more usual Parliamentary system of dealing with treaties. First, the President can only make Treaties with the consent of two-thirds of the Senate. That is why President Clinton signed Kyoto but did not ratify it, as the Senate voted preemptively 95-0 against consenting to any treaty that was agreed along Kyoto’s lines.
Secondly, and more importantly, treaties trump national law, having the same status as the Constitution. This means that activists can take the US Government to court and have national law quashed on the basis of a treaty commitment. Judges can also instruct the Federal Government to take steps to meet treaty commitments.