This week will be busy on Capitol Hill as 13 of President-elect Donald Trump’s nominees will be questioned by Senate committees.

While Trump cannot formally submit nominations until he is president—as he will do so shortly after taking the oath of office on Jan. 20—the committees can and will hold hearings featuring the nominees so they can be confirmed upon him entering office.

Constitutional Requirement

Almost all Cabinet nominees require Senate confirmation in accordance with the Constitution, which states that the president “shall nominate, and by and with the Advice and Consent of the Senate, shall appoint Ambassadors, other public Ministers and Consuls, Judges of the Supreme Court, and all other Officers of the United States, whose Appointments are not herein otherwise provided for.”

Going Before Committees

The nominees testify before the applicable committees. For example, Sen. Marco Rubio (R-Fla.), Trump’s pick for secretary of state, is scheduled to go before the Senate Foreign Relations Committee on Jan. 15, while Doug Burgum, the president-elect’s nominee to lead the Interior Department, is set to testify before the Senate Committee on Energy and Natural Resources, the day before.

Senators on committees will ask the nominees about their agenda if they are confirmed and test their knowledge about topics related to the portfolio they would take up if they get the job.

Committee Votes on Whether to Advance Nominees

Afterward, the committees will vote on whether to advance the nominee for a full vote on the Senate floor. A nominee being rejected by a committee does not mean that he or she cannot get a vote before the full Senate; therefore, the committee vote is non-binding.

Technically, it is not a constitutional requirement to have nomination hearings, as the Constitution does not explicitly state that nominees have to go before committees.

On the Senate Floor

Nominees need at least 51 votes, or a simple majority of the Senate, to be confirmed. Until 2013, nominations needed 60 votes to proceed to a final vote, which only required a simple majority.

Then-Senate Majority Leader Harry Reid (D-Nev.) abolished, or “nuked,” the 60-vote threshold, which requires most legislation in the Senate to clear in order to proceed to a final vote, for all nominees except those to the Supreme Court.

In 2017, then-Senate Majority Leader Mitch McConnell (R-Ky.) nuked the 60-vote threshold for Supreme Court nominees when he could not get enough Democrats to join all Republicans in getting three-fifths of the Senate to advance the nomination of Neil Gorsuch to the nation’s highest court.

In order for nominees to get confirmed by the Senate, Senate Majority Leader John Thune (R-S.D.) must file what is called cloture. After two days, the motion to invoke cloture is “ripened” and can be voted on. There is up to 30 hours of debate, though the Senate usually does not use all that time.

After debate on the nomination, the Senate votes on whether to confirm the nominee. The only executive branch nominee to be voted down was John Tower, whom former President George H.W. Bush picked as secretary of defense in 1989.

Recess Appointments

Finally, Trump has said he will use recess appointments to fill positions that require Senate confirmation. This could allow him to install people who may not otherwise get confirmed by the Senate.

Thune has not ruled out supporting recess appointments and has called for confirmation of Trump’s nominees “as soon as possible.”

The Constitution allows for recess appointments: “The President shall have Power to fill up all Vacancies that may happen during the Recess of the Senate, by granting Commissions which shall expire at the End of their next Session.”

Recess appointments, however, require the Senate to recess, which requires the chamber and the House to pass a resolution.

Although the GOP controls both houses of Congress, it is possible some moderate Republicans might object to recessing for such appointments.