He shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur; and he 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, and which shall be established by Law: but the Congress may by Law vest the Appointment of such inferior Officers, as they think proper, in the President alone, in the Courts of Law, or in the Heads of Departments. US Cont. Article II, Section 2
It was neither the intent nor understanding of the Founding Generation that the Senate may deny a president his nominee to a given appointed office, including that of the Supreme Court, solely for subjective, partisan reasons – a Senate hostile to a president for purely partisan reasons is not good cause to block an appointment; nor is there anything in the text, history, or jurisprudence of the Constitution to prohibit a president from making such an appointment at any time during his term as president, as his election reflects the will of the people, where such an appointment is consequently appropriate and warranted.