The Constitution divides responsibility between the executive and judicial branches - the president and the Senate.
A president’s most visible and consequential nomination may occur when a seat opens on the Supreme Court.
Historically, the Senate has confirmed most presidential nominations, but “in rare instances” a vote to confirm has failed.
"Americans tend to think of their president as the most powerful person in the world, but the Constitution limits the power of all three branches of government—the president as well as the Congress and the federal courts.In the case of filling top positions in the executive and judicial branches, the Constitution divides responsibility between the president and the Senate. Article II, Section 2 empowers the president to nominate and—“by and with the Advice and Consent of the Senate”—to appoint principal officers such as department heads as well as subordinate ones such as deputies.The process of the president’s nomination of Cabinet secretaries, and the Senate’s confirmation of them, is perhaps best known to the public but still somewhat mysterious.The Congressional Research Service, which studies and analyzes legislative matters for members of the Senate and House, breaks it down this way:First, the White House selects a prospective appointee and sends a formal nomination to the Senate.Second, the Senate determines whether to confirm the nomination.Third, the president presents a signed commission to the successful nominee and he or she is sworn in, assuming authority to carry out the duties of the office.The appointments clause of the Constitution specifies that the presidentshall 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, and which shall be established by Law.