On December 11, 2016, just before my time as secretary of defense ended, I stepped off a C-130 transport plane onto a cold and dusty patch of northern Iraq that had been on my mind for more than a year: an Iraqi military airfield called Qayyarah West. Q-West was a talisman of progress on one of the defining issues of my service, the fight to defeat ISIS. A year before, General Joe Dunford and I had briefed President Obama on a plan to step up the fight against ISIS.

How America, together with her friends and allies, turned the tide against a common enemy is a story of good fortune, critical leadership decisions, and skill and bravery on the part of young men and women in uniform.

"The liberation of Mosul and the inevitable, approaching liberation of Raqqa in Syria will not be the end of the Islamic State and its evil ideology. But they crush the group’s pretense to having an actual “state” based upon it. As its surviving leaders scurry to the corners of the desert, no longer can they claim to head a winning movement. Their defeat diminishes the inspiration for violent extremists, or simply lost souls on social media, to attack Americans and our friends. This is a necessary step forward in combating terrorism. Americans are safer for it."

For the seventh year in a row, Congress has failed to pass a defense appropriations bill in time to start the fiscal year. And for the past four years, the Defense Department and other federal agencies have been struggling with the impact of sequestration, which imposed cuts that were never meant to be implemented, but were supposed to prod both parties to come together and reach a budget agreement. The Defense Department has done its best to manage through this prolonged period of budget uncertainty, making painful choices and trade-offs among the size, capabilities and readiness of the joint force.

The nation cannot allow this to become the new normal.

"Iran's continued pursuit of an illicit nuclear program and North Korea's rash intimidation after sinking a South Korean navy ship are but the most recent reminders of the real need for effective U.S. missile defenses," write Under Secretary of Defense for Policy Michele Flournoy and Under Secretary of Defense for Acquisition, Technology and Logistics Ashton Carter.

President Barack Obama announced Monday that he has nominated Dr. Ashton B. Carter to serve as Under Secretary of Defense for Acquisition, Technology and Logistics.

Dr. Ashton B. Carter and Ambassador Robert G. Joseph discuss recommendations stemming from recommendations in final report of the review they co-chaired of the Defense Threat Reduction Agency (DTRA) and other DOD efforts to counter weapons of mass destruction.

A key challenge for the next administration's national security leadership concerns the management of investment in the U.S. national security future. In this paper for the Aspen Strategy Group, Dr. Ashton Carter discusses the challenges of defense budgeting and program selection, and the current mismatch between resources and strategy.

Full text of the trip report from PDP's Track II meetings in Taiwan and the People's Republic of China (PRC).