From CrashCourse

“Craig Benzine is going to tell you about the Supreme Court’s most important case, Marbury v. Madison, and how the court granted itself the power of judicial review. Judicial review is the power to examine and invalidate actions of the legislative and executive branches. It happens at both the state and federal court levels, but today we’re going to focus primarily on the court at the top – the Supreme Court of the United States. Now it’s important to remember that the court has granted itself these powers and they aren’t found within the Constitution, but as with the executive and legislative branches, the courts rely heavily on implied powers to get stuff done.”

Go to video (8:00): https://www.youtube.com/watch?v=mWYFwl93uCM ^[1]