The length of the appointment process during presidential transitions has been of concern to observers for more than 30 years. The appointment process is likely to develop a bottleneck during this time due to the large number of candidates who must be selected, vetted, and, in the case of positions filled through appointment by the President with the advice and consent of the Senate (PAS positions), considered by that body. By the end of the first 100 days of the Reagan presidency, nominees had been confirmed for 19% of vacant PAS positions. At the same juncture at the outset of the Clinton Administration, nominees had been confirmed for 11% of these openings. The figure for the presidency of George W. Bush was 7%, and for the Obama Administration was 14%. Delays in installing new leadership would not be welcome by an Administration at any time, but they may be particularly problematic during the transition period between Presidents. In 2004, the National Commission on Terrorist Attacks Upon the United States (known as the 9/11 Commission) identified what it perceived were shortcomings in the appointment process during presidential transitions that could compromise national security policymaking in the early months of a new Administration. The commission noted that a new President is likely to need his or her top advisers in place to maintain continuity in this area. Furthermore, the President has limited time following his or her election to initiate an administrative and legislative agenda. Presidential transitions involve large-scale changes in the political leadership of the executive branch. Table 1 summarizes Office of Personnel Management (OPM) data indicating that more than 2,600 political appointees occupied positions in the 15 departments as of June 30, 2016. These officials included top-level policymaking presidential appointees, political managers, and confidential support staff. Unlike career public service executives and employees, top political officials in the federal departments and agencies nearly always serve at the pleasure of the President or agency head. These officials typically resign when the Administration changes, especially if the incoming President is from a different party. This report describes and analyzes the processes, during a presidential transition, by which top-level executive branch PAS positions have been filled in the recent past. Outside of top White House staff appointments, these are a new President's earliest and arguably most important appointments. In the next section, the usual process is described in three stages: " Selection and Vetting ," " Senate Consideration ," and " Appointment ." That section also provides examples of ways the Senate has adapted its procedures during recent presidential transitions. The report then discusses processes—recess appointments and designations under the Federal Vacancies Reform Act of 1998—that could be used by the President to unilaterally fill positions on a temporary basis. The final portion of the report provides additional information on the length of time required in the past to fill Cabinet positions and certain national-security-related subcabinet positions. This section provides related data for the five transitions since 1980: Carter-Reagan (1980-1981), Reagan-Bush (1988-1989), Bush-Clinton (1992-1993), Clinton-Bush (2000-2001), and Bush-Obama (2008-2009). This report does not cover and will not track the 2016-2017 transition process. Under the Constitution, the power to appoint the top officers of the United States is shared by the President and the Senate. The appointment process consists of three stages—selection and vetting, Senate consideration, and appointment. In the first stage, the White House selects and clears a prospective appointee before sending the formal nomination to the Senate. With the assistance of, and preliminary vetting by, the White House Office of Presidential Personnel, the President selects a candidate for the position. Members of Congress and interested parties sometimes have recommended candidates for specific PAS positions. In general, the White House is under no obligation to follow such recommendations. In the case of the Senate, however, it has been argued that Senators are constitutionally entitled, by virtue of the advice and consent clause noted above, to provide advice to the President regarding his or her selection; the extent of this entitlement is a matter of some debate. As a practical matter, when Senators have perceived that insufficient pre-nomination consultation has occurred, they have sometimes exercised their procedural prerogatives to delay, or even effectively block, consideration of a nomination. Following this selection, the candidate needs to be cleared for nomination. During the clearance process, the candidate prepares and submits several forms, including the "Public Financial Disclosure Report" (Office of Government Ethics (OGE) 278), the "Questionnaire for National Security Positions" (Standard Form (SF) 86), a supplement to SF 86 ("86 Supplement"), and sometimes a White House Personal Data Statement. The clearance process often includes a background investigation conducted by the Federal Bureau of Investigation (FBI), which prepares a report that is delivered to the White House. It also includes a review of financial disclosure materials by the OGE and an ethics official for the agency to which the candidate is to be nominated. If conflicts of interest are found during the background investigation, the OGE and the agency ethics officer may work with the candidate to mitigate the conflicts. An incoming President can, of course, begin the process of selecting the members of his or her Administration at any time. During recent decades, most major candidates have begun preparing for a potential presidency before Election Day by assigning a small number of advisors to begin developing transition plans. Since 2008, candidates and their transition advisors have been aided in the selection of personnel by a provision of the Intelligence Reform and Terrorism Prevention Act of 2004 (known as the Intelligence Reform Act). This provision directs the Office of Personnel Management (OPM) to transmit an electronic record "on Presidentially appointed positions," with specified contents, to each major party presidential candidate "not later than 15 days" after his or her nomination. The provision permits OPM to make such a record available to any other presidential candidate after these initial transmittals. The Intelligence Reform Act also included several provisions that responded to 9/11 Commission recommendations regarding the vetting process. One provision of law permits each major party presidential candidate to submit, before the general election, security clearance requests for "prospective transition team members who will have a need for access to classified information" in the course of their work. The law directs that resulting investigations and eligibility determinations be completed, as much as possible, by the day after the general election. To the degree that transition team members go on to be nominees to positions in the new Administration, this proactive clearance process might also accelerate the transition period appointment process. The Intelligence Reform Act also amended the Presidential Transition Act of 1963 (PTA). The amendments included a provision stating that the President-elect should submit, as soon as possible after the presidential election, the "names of candidates for high level national security positions through the level of undersecretary" of agencies and departments. A second provision requires the responsible agency or agencies to carry out background investigations of these candidates for high-level national security positions "as expeditiously as possible ... before the date of the inauguration." More broadly, the PTA authorizes the General Services Administration to provide resources, services, and other support associated with the presidential transition process. In earlier decades, this support was provided only after a presidential election. Since the publication of the report of the 9/11 Commission, however, this statute has been amended to authorize support for eligible candidates prior to the election. As just noted, it was amended in 2004 by the Intelligence Reform Act. Further amendments came in 2010 and 2016. The aim of extending the act to encompass the pre-election period was to "strengthen the transition planning of the multiple parties whose active involvement is necessary for a successful transition: the incumbent president, major candidates, the president and vice-president-elect, senior career officials across the government, and the transition support team at GSA." These latter amendments were first implemented during the 2016-2017 presidential transition. As amended, the PTA directs the President and incumbent Administration to establish a specified transition-related organizational infrastructure as well as to provide certain pre-and post- election support to eligible candidates and then to the President-elect. The statute also authorizes eligible candidates to fund pre-election transition activities through their campaigns. Arguably, beyond the provisions of the PTA that specifically apply to the selection and vetting of an incoming President's leadership team, the infrastructure and support provided for in the statute create conditions that have the potential to enhance, more generally, the ability for an incoming Administration to carry out these activities. Once the President has selected and vetted an individual and submitted a nomination, the Senate determines whether or not to confirm the nomination. Once received from the President, each nomination is referred to the committee with jurisdiction over the agency in which the nominee would serve or the subject matter related to the nomination. Action at the committee level is at the discretion of the committee chair. No Senate or committee rule requires that a committee, or the full Senate, act on any nomination. Most nominations, however, proceed through the process in a routine, timely fashion. During the 111 th Congress (2009-2010), the first Congress of the Obama Administration, the Senate took a median of 52 days to confirm a nomination to a full-time departmental position. The Senate confirmation process begins at the committee level. The rules and procedures of the committees frequently include timetables specifying minimum periods between steps in the process. Committee activity on nominations generally includes investigation, hearing, and reporting stages. During the investigation phase, many committees require nominees to fill out questionnaires that the committee has prepared and to provide financial and biographical information. If the committee acts on a nomination, the process typically begins with a hearing, where the nominee and other interested parties may testify and Senators may question the nominee. After the hearing—if there is one—the committee usually votes on reporting the nomination to the Senate.