Ashton Carter, US defence secretary, 1954-2022

Ashton Carter, who served as the US defence secretary under former president Barack Obama, began his career as a physicist. He first came to prominence as a young scholar when he published a paper for a Congressional office debunking Ronald Reagan’s “Star Wars” anti-ballistic missile programme. The paper raised his profile within the national security community, and gave him a taste for politics as well as policymaking.

Carter, who has died aged 68, went on to serve under five presidents in different roles. He was known for opening up all combat positions to women, as well as for his insistence that the US military invest in more advanced technology.

Carter was born in 1954 in Philadelphia to a neurologist father and an English teacher mother. He double-majored in medieval history and physics at Yale University and was a Rhodes scholar at Oxford university, where he studied physics.

In his 2019 memoir he wrote that Bill Clinton was the first president he got to know well, when he served as assistant secretary of defence for international security policy. He was impressed when Clinton made a beeline for him after a meeting with then Russian president Boris Yeltsin, and apologised for failing to bring up one of Carter’s priorities. Carter later helped write the legislation that secured and dismantled nuclear weapons in the former Soviet Union, including in Ukraine.

Carter took office as defence secretary when the Obama administration was involved in the campaign to push back against Islamic State militants in Iraq and Syria. In his multiple roles during the Obama years, he also directed the US military’s sights towards the rise of China.

When he first joined the Obama administration in 2009, thousands of American troops were dying or suffering severe injuries because the vehicles they operated in Iraq and Afghanistan didn’t offer enough protection. Carter devoted energy as the top procurement officer to speeding up the development and delivery of Mine Resistant Ambush Protected vehicles, known as MRAPS. He later cited that project as one of his proudest accomplishments.

“It was really Ash’s understanding of the system, and not being willing to take first reports . . . which drove that effort,” said Sally Donnelly, who advised him in and out of the Pentagon, referring to initial assessments about how to fix the vehicle problem.

Speaking to defence leaders at the White House on Wednesday, President Joe Biden singled out Carter’s efforts to deliver MRAPs, which he said the US had originally intended to postpone. “I’ll never forget working with him to make sure that our troops in Iraq and Afghanistan . . . had those life-saving, limb-saving MRAPs they needed,” Biden said. “It saved a hell of a lot of lives . . . I deeply valued Ash’s courage and counsel during that point.”

Friends and colleagues described him as smart, thoughtful and generous, but at times impatient or combative. In his memoir he recalled his frustrations at times with the Obama administration’s policymaking, particularly the National Security Council’s overemphasis on discussing military matters, which he described as “‘playing with little tin soldiers’ — not a very good use of our time”.

Carter also spent time at both Harvard and Stanford universities. But his stint at Stanford ended soon after it began, when he returned to the Obama administration in 2015. Upon announcing his nomination as defence secretary, Obama joked that Carter had “failed miserably” in his one-year attempt to retire.

Though Carter never served in the military, his many years in and around the Pentagon meant he understood its inner workings. Colleagues described him as one of the best prepared people to ever lead the US department of defence. Carter was one of the few people to have held four of the top jobs at the Pentagon.

Observing the rise of Donald Trump, Carter said in his memoir that he always tried to be useful to Republicans and Democrats, and worried that Washington was becoming less bipartisan. “He was somebody who was respected in both parties,” said Paul Haenle, a China expert and former senior government official who studied under Carter at Harvard.

The day before he died, Carter hosted a lunch for Kurt Campbell, now deputy assistant to the president and co-ordinator for the Indo-Pacific. Carter, who in his book described himself as a “scientist at heart,” left the lunch early, ducking out to teach a class at Harvard.

“With a twinkle in his eye, he ran to class where the topic of the day was cloning, CRISPR, and the implications for human life,” said Harvard professor Graham Allison.