In the hands of a scholar

President Barack Obama was full of praise when he announced his choice for Chuck Hagel's replacement in December, lauding Ashton Carter as a person who was "rightly regarded as one of our nation's foremost national security leaders." The president paid explicit tribute to Carter's "innovation" in the Pentagon and his tenure with regard to US defense policy, making it clear that the 60-year-old had more than enough experience to do the job. "He was at the table in the Situation Room; he was by my side in navigating complex security challenges."

Staring directly at Obama, Carter responded to the presidential praise with two promises:

"If confirmed in this job, I pledge to you my most candid strategic advice," he said. And that he would "keep faith with the greatest fighting force the world has ever known."

Pragmatic technocrat

Over the past two decades in and out of the Pentagon, Carter has built a reputation for being an assertive technocrat with sterling knowledge of US weapons arsenals and the workings of the department of defense - and a proclivity for pragmatic decision-making.

Former Pentagon colleagues, including Defense Secretary William Perry, under whom Carter served as assistant during the Clinton administration, have described him as "efficient," "calculating," even "hard-nosed" when it comes to the use of force in implementing US defense policy.

He was Obama's chief weapons buyer from 2009 to 2011 and after that served as Pentagon number two until 2013. His deep knowledge of Pentagon budgetary affairs will come in handy amid a resounding White House and Congressional desire to cut military spending across the board. A characteristically pragmatic Carter has expressed willingness to decrease spending, but only where that spending is "unnecessary."

"Carter's great strength is his weakness," said John Hulsman, a German-based American foreign policy expert. "He is seen as a superb technocrat who knows how to make the unwieldy Pentagon work. As such, he is truly respected on both sides of the aisle," Hulsman told DW.

Despite his expertise and his political acumen, however, the question remains whether his vision for the US role in the world - given domestic qualms at home - is a viable one.

"He really isn't a grand geostrategist - and one is needed now to make sense of the multipolar world," Hulsman said, concluding that Carter's impact as defense secretary "may be limited."

A quantum leap to defense policy

Carter's reputable expertise and interest in defense policy follows, almost bizarrely, an academic career in which he dedicated himself to the study of theoretical physics. He double majored in medieval history and physics at Yale and earned his doctorate as a Rhodes Scholar at Oxford, envisioning theories about quantum chromodyamics, i.e., the behavior of sub-atomic particles in nuclear reactions.

"In [Carter] you have a poster child for the guy who discovers that science and technology are the major drivers for some of the most important events in international affairs, and sometimes are the sources of the solutions," Graham Allison, who recruited Carter to work for the Belfer Center for Science and International Affairs at Harvard's Kennedy School, told the New York Times ahead of Wednesday's Senate hearing.

In a short autobiography published on the Kennedy School website, Carter explains that the motivation for his jump from academia to the political realm was inspired by the Cold War. "The enormity of the dangers could not be ignored," he wrote, with reference to the year 1979. "I flattered myself into believing that the two poles of my training, physics and history, came together in the effort to cope with the [potential destructiveness of the] Cold War."

And with regard to Washington, Carter writes: "Public service at senior levels is a little bit like being a Christian in the Coliseum. You never know when they are going to release the lions and have you torn apart for the amusement of onlookers."

Carter concludes that in the face of the "whirlwind" that is Washington the only thing that can help is "having an agenda," and the faith to say what he feels in the face of the lions. And those were indeed the two promises he made when Obama picked him for the Pentagon's top job.