Principal Deputy Under Secretary of Defense

Principal Deputy Under Secretary of Defense (PDUSD) is the title for several high-ranking posts in the U.S. Department of Defense. Formerly, there also existed the position of Deputy Under Secretary of Defense (DUSD). Some of these positions require appointment by the President and are confirmed by the Senate by majority vote. There are currently five PDUSDs and no DUSDs. The use of these titles was severely restricted by the FY2010 and FY2011 National Defense Authorization Act (NDAA). PDUSDs and DUSDs report, either directly or indirectly, to an Under Secretary of Defense.

There currently exist five PDUSDs. Each PDUSD is appointed by the President and confirmed by the Senate. The five PDUSDs are:

Each of the PDUSDs serves as the "first assistant" to the corresponding Under Secretary of Defense, and would serve as the acting Under Secretary in the Under Secretary's absence. The PDUSD is not "directly responsible for a specified portfolio within the Office of the Under Secretary," but instead is responsible for assisting the Under Secretary with the entire portfolio. Reporting to the PDUSDs are Assistant Secretaries of Defense, who are appointed by the President and confirmed by the Senate, and Directors, Directors of Defense Intelligence, and similar positions, who are not subject to Senate confirmation. The PDUSD for Intelligence is required by law to be "appointed from among persons who have extensive expertise in intelligence matters."

The position of Deputy Under Secretary of Defense no longer exists, except for the five PDUSDs listed above.

The title Deputy Under Secretary of Defense was first used in 1986 with the creation of the position of DUSD for Acquisition. Initially, differentiation between the PDUSD and DUSD was not clear, with some positions officially referred to by both titles. By 2009, there were 29 PDUSD and DUSD positions. Five of these positions were established by statute of which four required confirmation by the Senate. Others were created by the Department of Defense itself. Four of the DUSDs were designated either by Congress or by DOD to be "Principal Deputy" for the Undersecretary. These DUSDs were known as PDUSDs. The reporting relationship between the DUSDs and other senior leaders in the department was not uniform. Some DUSDs reported directly to an Under Secretary of Defense, while others reported to a PDUSD, another DUSD, or another Providentially appointed senior official. Four of the five Under Secretaries of Defense had a PDUSD reporting to them, of which two were designated by Congress and appointed by the President.

...
Wikipedia