The Supreme Court
The country's final legal authority is the Supreme Court. It has the responsibility to interpret the law and reject legislation or executive actions it deems in violation or contradiction of the Constitution. Several presidents have seen their powers restricted by court rulings that struck down their programs or restricted their orders.
Since Supreme Court justices are appointed for life, they are largely sheltered from political pressure. All a president can do to affect Supreme Court outcomes is try to amend the Constitution or hope that vacancies open up on the court, giving him an opportunity to name more sympathetic justices.
Court packing cartoon
In the mid-1930s the Supreme Court ruled many of President Franklin D. Roosevelt's New Deal reforms, including the National Industrial Recovery Act, unconstitutional. Roosevelt countered by proposing to enlarge the size of the court and thus, through his new appointees, win more favorable decisions.
Both Republicans and Democrats were outraged by this attack on the court's independence and forced Roosevelt to withdraw his proposal. No president since has attempted to directly undermine the court's constitutional autonomy, and the size of the court has remained fixed (since 1869) at nine justices. This cartoon by Elderman appeared in the February 6, 1937, Washington Post.