Why Are There 9 Supreme Court Justices?

With the announcement of President Obama's next Supreme Court justice nominee looming, attention has focused on how the newest addition will affect the balance of the court's voting. The ninth justice may be the swing vote in future court cases.

The original U.S. Constitution did not set the number of justices on the Supreme Court. Therefore, it was up to Congress to decide, and in 1801, it set the number at five. But things didn’t stay that way for long.

"The number of Supreme Court justices has changed over the years," Kathy Arberg, spokesperson for the U.S. Supreme Court, told Life's Little Mysteries. "The number of justices has been as high as ten.”

Congress increased the number to seven in 1807, to nine in 1837, then to 10 in 1863.

Then, in order to prevent President Andrew Johnson, who was soon to be impeached, from naming any new Supreme Court justices, Congress passed the Judicial Circuits Act of 1866. This Act reduced the number from 10 to seven. The decrease was to take effect as the seats became vacant.

However, only two seats were freed up by 1869, so there were eight justices. Congress added one seat back in, and decided that there should be nine justices. The Judiciary Act of 1869 officially set the number, and it has not budged since.

While the justices are appointed to serve a life term, some choose to give up their spots voluntarily. The justice set to retire soon is John Paul Stevens, who is among the Court's most liberal jurists, according to the New York Times Supreme Court Guide.

President Obama is in the process of deciding who to nominate to take his place.

"There are no official qualifications to become a justice, although most justices have a background in the law," Arberg said. "When there is a vacancy on the Supreme Court, the president nominates someone who then has to be approved by a majority vote in the Senate."