KNOXVILLE, Tenn. (WATE) — With Supreme Court Justice Stephen Breyer expected to retire, many are asking what comes next.

The process to appoint a new Supreme Court justice may look simple on paper, but in practice it can be complicated and contentious. This was seen when both Justice Amy Coney Barrett and Justice Brett Kavanaugh were appointed.

1. A seat opens on the Supreme Court

The process begins when a current justice chooses to retire or dies. Supreme Court justices serve for life once appointed. Justices can also be impeached from the court, although the only justice ever to be impeached was Associate Justice Samuel Chase in 1805. The House of Representatives passed Articles of Impeachment against him; however, he was acquitted by the Senate.

There are currently nine Supreme Court justices. However, it hasn’t always been that way. In 1789, the first Judiciary Act set the number at six. Over the next 80 years, Congress passed various acts to change the number, fluctuating from a low of five to a high of 10. The Judiciary Act of 1869 fixed the number of justices at nine, and it has not changed since.

2. President announces the nomination

The president will then nominate a candidate. According to the Constitution, anyone may be nominated for the role. However, all previous justices have been trained in the law and most have gone to law school and practiced law. The last justice who did not attend law school was James F. Byrnes who served on the court for 16 months beginning in 1941. According to the Court, he did not graduate from high school and taught himself law, passing the bar at 23.

3. Senate Judiciary Committee votes on the nominee

After the president’s nomination is announced, the Senate Judiciary Committee holds a hearing on the nominee. Prior to the hearing, the committee gathers information about the nominee from the FBI and other sources. This process usually takes about a month.

During the hearing, senators have the opportunity to question the nominee on their qualifications and judgment to get an idea of how they will make rulings. Witnesses both for and against the nominee will share information about them.

4. Senate votes on the nominee

The Judiciary Committee then votes on the nominee and sends its recommendation to the full Senate, who will debate the nomination. The nomination will be debated for a minimum of 30 hours unless the minority party agrees to a shorter schedule.

Once the debate ends, senators vote on the nominee. Since 1967, every Senate vote to confirm a Supreme Court justice has been formally recorded. In the past, confirmation votes have been the result of an overwhelming majority in favor. However, the previous three confirmation votes have been mostly along party lines. It only takes 51 votes to confirm the nominee. If the nominee is not confirmed the process starts over.

5. New justice joins the court

After the Senate votes to approve the new justice, they will take two oaths of office: the Constitutional Oath and the Judicial Oath.

In total, there have been 103 Associate Justices appointed to the Court since its inception.

Each term, the Court receives approximately 7,000-8,000 petitions for a writ of certiorari, a request that the Supreme Court order a lower court to send up the record of a case for review. The Court grants and hears oral arguments in about 80 cases each term. The first meeting of the Court took place Feb. 2, 1790.