Final answer:
Judicial review is the power of the courts to overturn laws or other actions of Congress and the Executive Branch based on their constitutionality. The Supreme Court established this power in the case of Marbury vs. Madison. It is rarely used.
Step-by-step explanation:
Judicial review is the power of the courts to overturn laws or other actions of Congress and the Executive Branch based on their constitutionality. This principle allows courts to establish quasi-legislation (legislation created from the bench) which often leads to accusations of "judicial activism". The Constitution is actually silent on the subject of judicial review, so the Supreme Court gave itself and lower courts the power of judicial review in the case of Marbury vs. Madison. Judicial review is rarely used, with the Court striking down only around 170 national laws and around 1400 state laws in its more than 200-year history.