Pentagon leaders will soon brief President Obama on the Quadrennial Defense Review and seek his approval of key elements, InsideDefense.com has learned. The upcoming session, tentatively slated for December, will allow Defense Department officials to request final approval of proposed QDR themes and initiatives, according to DOD documents. The meeting will build on the QDR and budget talks that Obama and Vice President Biden held with Defense Secretary Chuck Hagel, Chairman of the Joint Chiefs of Staff Gen. Martin...