Ash Carter guests hosts an hour of CNBC's Squawk Box. December 13, 2018.

Former U.S. Defense Secretary Ash Carter speaks with The WorldPost’s editor in chief, Nathan Gardels, about the Trump administration’s new China policy, North Korea and the pending U.S. withdrawal from the Intermediate-Range Nuclear Forces Treaty.

To understand how I approached China during my time as Secretary, it’s important to note that I don’t see U.S. strategy in Asia as centered on China at all. I said many times: We don’t have a China policy, we have an Asia policy. The heart of that policy is a mesh of political, diplomatic, economic, and military relationships with many nations that has sustained security and underwritten an extraordinary leap in economic development.

During my time as Secretary, I referred to this structure over and over as the “principled, inclusive network.” Enunciating and reinforcing its strategic and military dimensions in a rapidly changing security environment was my constant priority as Secretary of Defense. Even amid pressing challenges such as the fight against ISIS and the need to confront Russian aggression, no other issue I dealt with had such lasting implications for our national security and prosperity.

My three-word title for this policy was admittedly not very catchy. But my counterparts in the region understood it. They understood that all three words have been essential to its success and will remain essential to its future.

Ash Carter is a physicist and a defense-policy expert, having served in government periodically for decades. He was secretary of defense from 2015 to 2017. He has spent his academic career at Harvard, where he is today. In this “Q&A,” Jay Nordlinger asks him about some of the biggest issues: nuclear proliferation, North Korea, Iran, the size of the U.S. military. He also asks about the relation between our servicemen and the general American population. Is there too great a gulf between them? Do people sentimentalize our military? Is it okay to say “Thank you for your service”?

On December 3, 2015, then Secretary of Defense Ash Carter made an announcement that would transform the U.S. military: all combat jobs in every branch of the military would be open to women. At a Harvard Kennedy School event this fall, Carter talked about his historic decision.

By working together, I am confident we can succeed, because in many ways we already have. If we think back to those defense investments and decisions that changed the course of our nation’s and our military’s history for the better — and not just in technologies like GPS, the Internet, and satellite communications, but also in other areas, like the all-volunteer force — they were all able to benefit our security and our society because they garnered support across the aisle, across branches of government, and across multiple administrations.

"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.

PDP Co-Director Dr. Ashton B. Carter explores the daunting list of national security challenges facing the next American president.

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.