With the death of Justice Ruth Bader Ginsburg creating a vacancy in the United States Supreme Court, membership of the high court is down to eight. Much attention is focused on who will bring that number back up to nine. While we are used to having nine members of the Supreme Court, it hasn’t always been that way, and there is no guarantee it will always remain so.

Article III, Section 1 of the U.S. Constitution states that the “judicial power of the United States shall be vested in one Supreme Court, and in such inferior courts as Congress may from time to time ordain and establish.” The Constitution also establishes the position of Chief Justice of the United States. Beyond that, it is silent about how the Court should be staffed. It is up to Congress to determine the number of justices. The only restriction is that once someone is installed on the Court, he or she has the right to remain there, as long as the individual does not misbehave. In other words, Congress can create new positions on the Court at any time, but it may only decrease the number of seats when there is a vacancy.

The Judiciary Act of 1789 set the number for the first Supreme Court at six: a chief justice and five associate justices. The first session of the Court is noteworthy for not hearing a single case or issuing a single ruling. Only five of the six seats had been filled, and only four of the justices convened. The first case docketed to come before the Court was Van Staphorst v Maryland (2 U.S. (2 Dall.) 401) in 1791. It was resolved before the Court could hear it, however. It wasn’t until West v Barnes (2 U.S. 401 (2 Dall.) 401) that the Court finally got to hear a case. Oral arguments were held on August 2, 1791. The Court issued its opinion the next day.

An 1801 act would have decreased the Court’s size to five members upon its next vacancy. However, an 1802 act negated the effects of the 1801 act upon the Court before any such vacancy occurred, maintaining the Court’s size at six members.

Congress decided in 1807 to increase the size of the Court to seven. Thirty years later, it increased the number to nine. In 1863, the Court grew to its largest size to date, when Congress increased its membership to ten.

The primary factor driving the size of the Court at that time was not its case load. In 1864, the year after the Court’s size was raised to ten, it handled only seven cases for the entire year. More pressing was the dual nature of the justices’ responsibilities. In addition to sitting as a member of the Supreme Court, each justice was also expected to ride circuit and preside over multiple lower-court cases each year. The need for more justices was because of the number of federal circuits.

In 1866, Congress passed the Judicial Circuits Act. It reorganized the U.S. circuit courts and reduced the size of the Supreme Court from ten to seven. It also had the political effect of Congress preventing President Andrew Johnson from getting a chance to appoint anyone to the Court.

The Act provided: “Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That no vacancy in the office of associate justice of the supreme court shall be filled by appointment until the number of associate justices shall be reduced to six; and thereafter the said supreme court shall consist of a chief justice of the United States and six associate justices, any four of whom shall be a quorum; and the said court shall hold one term annually at the seat of government, and such adjourned or special terms as it may find necessary….” (emphasis added)

There were two vacancies after the enactment of the Judicial Circuits Act, bringing the number of Court members down to eight. Before another vacancy could occur, however, Congress made another revision. In 1869, the number of justices was raised to nine. It has remained at this number ever since.

That’s not to say there haven’t been attempts to change the size of the Court in the past 150 years. Most notably, President Franklin D. Roosevelt, out of frustration that the Court kept invalidating his New Deal programs, proposed increasing the number of justices to as many as 15. This proposal failed to gain traction with Congress, however, and it became a political embarrassment for FDR. Since then, “court packing” has ranked among the top of worst-thought-through political experiments.

As previously noted, once a Supreme Court justice takes office, it is not very easy to remove him or her. The appointment is typically described as being for life, but the Constitution actually says they shall hold their office “on good behavior.” In other words, absent death or resignation, the only way to remove a justice is by impeachment. Only one justice ever has been impeached: Samuel Chase, in 1804. The U.S. House of Representatives voted to impeach Chase, an outspoken figure accused of acting in a partisan way during various court proceedings. He was acquitted by the U.S. Senate, however, and continued to serve for another six years until his death in 1811.

The only justice to be unseated involuntarily was Chief Justice John Rutledge. When Chief Justice John Jay resigned on June 28, 1795, President George Washington used the Constitution’s recess appointment provision to appoint Rutledge as Chief Justice. The Constitution permits the President to make appointments when the Senate is not in session, but any such appointment will automatically expire at the end of the next session of Congress unless confirmed by the Senate.

Washington appointed Rutledge on June 30, 1795. Two weeks later, Rutledge gave a speech in which he voiced strong opposition to the Jay Treaty with Great Britain. He said that he would “rather the President should die than sign that puerile instrument” and that he “preferred war to an adoption of it.” These less-than-judicial remarks cost him the support of the Federalist Party. When his nomination came up for Senate consideration on December 15, 1795, it was defeated, by a vote of 14-10. To say this was disappointing to Rutledge is an understatement. He attempted suicide 11 days after the Senate vote by jumping off a wharf into Charleston Harbor. Although he could have remained on the Court through the end of the Congressional session the following June, Rutledge resigned from the Court on December 28, 1795, having served just 138 days as Chief Justice of the United States.

Despite Rutledge’s experience, recess appointments have not been that uncommon. In addition to Rutledge, one other Chief Justice (Earl Warren) and ten associate justices received recess appointments. In fact, all three of President Dwight D. Eisenhower’s Supreme Court nominees (Warren, William Brennan, and Potter Stewart) started off as recess appointees. Stewart’s appointment in 1959 was the last such appointment.

The more traditional ways for members of the Court to depart are by death or resignation. There seem to be periods in which one method prevails heavily over the other:

Certainly, departure by death is far less common than it used to be. Following Justice Robert Jackson’s death in 1954, it would be a full 51 years before the Court saw another colleague die in office (Chief Justice William H. Rehnquist).

Part of the reason for fewer deaths these days is the ever-growing lifespan for Americans. Seventeen of the first 38 justices to die while in office died prior to their 70th birthday, and four of these, James Wilson (56), James Iredell (48), Robert Trimble (52), and Philip Pendleton Barbour (58), died before reaching the age of 60. In contrast, the seven justices who have retired since 1990 — David Souter (age 69), John Paul Stevens (90), Sandra Day O’Connor (75), Anthony Kennedy (82), Harry Blackmun (85), Byron White (76), and Thurgood Marshall (83) — had either reached or were approaching, their 70th birthdays at the time they stepped down.