US President-elect Donald Trump with his pick for Defence Secretary James Mattis.
Retired General James Mattis, poised to become the first career military officer in charge of the Pentagon since the 1950s, said on Thursday that he believes Russian President Vladimir Putin is trying to "break" the NATO alliance that has anchored American and European security for more than half a century.
Under questioning at his Senate confirmation hearing, Mr Mattis portrayed Russia as a strategic adversary. He said the history of US-Russian relations is short on successful efforts at lasting cooperation, something President-elect Donald Trump has pledged to pursue.
Of Mr Putin, said Mr Mattis, a former NATO military leader: "He is trying to break the North Atlantic alliance."
Mr Mattis said that while the US should remain open to working with Russia, the prospects for cooperation are narrowing.
The context was clear. As he spoke, Mr Trump's choice to run the CIA was testifying before another Senate panel and was sure to be questioned at length about the US intelligence agencies' allegations that Moscow interfered in the presidential election. Ties between the former Cold War foes also have been strained by Ukraine and Syria.
More broadly, Mr Mattis said the world order was under "the biggest attack since World War II," blaming Russia, China and international terrorist organizations for destabilizing trends and actions.
Asked by Senator John McCain, the Armed Services Committee's Republican chairman, whether the US military was fully ready to confront these challenges, Mr Mattis replied: "No, sir."
In prepared testimony, Mr Mattis said he understands his role as the Defense Department's civilian leader would be different "in essence and in substance" from his four decades in uniform.
"The esprit-de-corps of our military, its can-do spirit and its obedience to civilian leadership reduces the inclination and power of the military to criticize or oppose the policy it is ultimately ordered to implement," Mr Mattis said. He called civilian control "a fundamental tenet of the American military tradition."
Mr Mattis, 66, retired in 2013 after serving as commander of US Central Command in charge of all US forces in the Middle East.
He is known for strong views on Iran. Mr Mattis sees Tehran as a menace in the Middle East, and would work for a president who has pledged to toughen US policy toward Iran. That could have broad implications as the incoming administration weighs modifying the 2015 Iran nuclear deal and reconfiguring American posture in the Middle East after complaints from US allies that President Barack Obama yielded too much ground to Tehran.
The last career military officer to serve as defense secretary was George Marshall in 1950-51.
In his opening remarks to senators, Mr Mattis expressed unqualified support for traditional US international alliances. In contrast, Mr Trump insisted during the presidential campaign that US treaty allies and security partners should pay more for their own defense and for hosting American forces on their soil.
"History is clear: Nations with strong allies thrive and those without them wither," Mr Mattis said.
Before Mr Mattis can join the Cabinet, Congress must approve a one-time exception to a law requiring a military officer to be out of uniform for at least seven years before leading the Pentagon. Even some of Mr Trump's strongest critics say Mr Mattis merits the exception.
Eliot A Cohen, a senior State Department counselor in President George W Bush's administration who has publicly criticized the incoming Trump team, said at a Senate hearing this week that he feels a "sense of alarm" about the judgment of the incoming administration. But he said Mr Mattis "would be a stabilizing and moderating force, preventing wildly stupid, dangerous or illegal things from happening."
Mr Trump has selected two other recently retired generals for top jobs in his administration.
Michael Flynn, who left the Army as a lieutenant general in 2014 after a tumultuous tenure as the Defense Intelligence Agency's director, is Mr Trump's national security adviser. Marine General John Kelly, who retired in 2016, was chosen to head the Department of Homeland Security.