In the United States of America, why does the Supreme Court possess a significant zone of discretion in…

The U.S. Supreme Court exercises wide discretion in constitutional interpretation because the U.S. Constitution is a brief, broadly phrased document (including the Ninth Amendment and the Due Process Clauses) through which the Court has recognized and interpreted unenumerated rights such as the right to privacy, combined with a rigid amendment procedure. By contrast, U.S. Supreme Court justices are appointed (not elected), statutes do not require pre-enactment judicial approval, and constitutional amendments require supermajorities.