It depends on what the meaning of the word shall is, says Seth Barrett Tillman:
Now the people who have opined that President and/or Senate have a constitutional duty (per the Appointments Clause) to nominate a successor to AS are distinguished commentators, whose opinions deserve fair consideration. However, there are people who have taken the opposite position. These include, for example, Professors Lawson and Seidman, Adam J. White, a well-published D.C. practitioner, and Daniel Koffsky, a senior Department of Justice attorney. See, e.g., Gary Lawson & Guy Seidman, Downsizing the Right to Petition, 93 Nw. U. L. Rev. 739, 762 n.123 (1999) (“[T]he Appointments Clause is best read as a grant of power rather than an affirmative duty.”); Adam J. White, Toward the Framers’ Understanding of “Advice and Consent”: A Historical and Textual Inquiry, 29 Harv. J.L. & Pub. Pol’y 103, 147 n.235 (2005) (“[T]he President is under no duty to nominate someone to fill a vacant office—despite the Constitution’s instruction that he ‘shall’ so nominate . . . .”); cf., e.g., Appointment of a Senate-Confirmed Nominee, Op. Off. Legal Counsel 232, 232 (Oct. 12, 1999) (Koffsky, Acting Deputy Asst. Att’y Gen.) (“The Constitution thus calls for three steps before a presidential appointment is complete: first, the President’s submission of a nomination to the Senate; second, the Senate’s advice and consent; third, the President’s appointment of the officer, evidenced by the signing of the commission. All three of these steps are discretionary.”), http://tinyurl.com/gljnnv8. These people are also distinguished commentators, whose opinions deserve fair consideration.
Here we are faced with what are essentially conflicting intuitions in regard to the original public meaning of an 18th century text. Both sides cannot be correct. What to do? We should look for evidence, and fortunately, some good evidence is at hand.
Read the whole thing.