What is the appropriate role of the judiciary in a separation of powers system? Does the judicial branch today operate the way the Framer's of the Constitution intended it to?

Under the doctrine of the separation of powers, the judiciary generally does not make law  but rather interprets law and applies it to the facts of each case. Our Founders envisioned a judicial system separate from the political branches of government, a system designed to fulfill the promise that this country would provide a government based on the rule of law. The constitution doesn't directly address whether or not courts were to be given such power. It's possible the Framer's of the Constitution figured that the structure of the governent would have made their intentions abundantly clear.