The federal government selects candidates for high-level positions in the executive branch and in the judiciary in one of two ways: Senate confirmation or recess appointment.
The Constitution’s Appointments Clause  stipulates,
The Constitution’s Recess Appointments Clause  empowers the president to fill high-level positions in the executive branch and in the judiciary temporarily without Senate approval.
Both ways of selecting high-level candidates for executive and judicial positions require the president and the Senate to act jointly. Senate confirmation requires senators to approve the president’s nominees. Recess appointment requires the Senate to adjourn for a sufficient period of time for the president to fill vacancies temporarily.
Both approaches also present Senate majorities and presidents with challenges to their confirming more nominees and making recess appointments. Senate confirmation gives a minority of senators an opportunity to slow down the confirmation process by filibustering (or threatening to filibuster) presidential nominees. Such obstruction forces Senate majorities to use the time-consuming cloture process to schedule up-or-down confirmation votes for nominees. Minority obstruction (or threats to obstruct) therefore limits the number of presidential nominations that the Senate can approve in a two-year period.
Recess appointment similarly requires senators to act prior to the president filling vacancies temporarily. In this case, senators must first vote to adjourn the Senate instead of voting to confirm the president’s nominees. The Constitution requires that the House of Representatives first consent to the Senate adjourning for more than three days. The Adjournment Clause  stipulates,
In 2014, the Supreme Court expanded the three-day threshold to ten days for recess appointments made during an intra-session recess of the Senate (i.e., recesses that occur entirely within a single year during a particular Congress’s two-year existence). According to the Court’s opinion in National Labor Relations Board v. Noel Canning et al. 
The Constitution’s requirement that the House approve the Senate’s adjourning for more than three days and the Supreme Court’s ruling in National Labor Relations Board v. Noel Canning et al. likely limits presidents’ ability to make recess appointments in periods of divided government. For example, the Democratic-controlled House is unlikely to approve a request by Senate Republicans to adjourn for more than ten days so that President Trump can make recess appointments.
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- “Appointments Clause”: https://www.archives.gov/founding-docs/constitution-transcript#toc-section-2--2
- “Recess Appointments Clause”: https://www.archives.gov/founding-docs/constitution-transcript#toc-section-2--2
- “Adjournment Clause”: https://www.archives.gov/founding-docs/constitution-transcript#toc-section-5-
- “National Labor Relations Board v. Noel Canning et al.”: https://www.oyez.org/cases/2013/12-1281
- “turtix”: https://www.shutterstock.com/g/turtix