WASHINGTON — Retired Marine General James Mattis, Donald Trump’s pick to be the next defense secretary, placed Russia first among principal threats facing the United States, arguing for greater American support for European allies to counter what he said were Moscow’s attempts to shatter the North Atlantic security alliance.
Mattis, a respected combat leader who made his name in the wars following the Sept. 11, 2001, attacks, cautioned that sustained cuts to military budgets and personnel meant the US military is no longer strong enough to easily outmatch Russia and other adversaries.
Mattis’s remarks during his confirmation hearing Thursday provide some of the first hints about how the Trump administration, which has not put forward comprehensive national security plans, may alter the posture of the world’s most advanced military at a time of institutional strain and uncertainty about the future.
His comments also signal a possible divergence in viewpoint with the president-elect, who has questioned longstanding security commitments and voiced his willingness to partner with Russia’s president, Vladimir Putin. Trump said at a news conference Wednesday that ‘‘Russia can help us fight’’ the Islamic State, but he also noted: ‘‘I don’t know that I’m gonna get along with Vladimir Putin. I hope I do. But there’s a good chance I won’t.’’
Mattis’s seeming differences with Trump and those with the president-elect’s pick to be secretary of state, Rex Tillerson, who unlike Mattis has suggested that he might support renegotiating President Obama’s nuclear deal with Iran, could lead to a fractious approach to foreign policy and interagency feuding in the next administration.
Mattis spoke as Representative Mike Pompeo, a Kansas Republican whom Trump has tapped to lead the CIA, pushed back on Trump’s support for waterboarding during the campaign and said he would reject orders to torture detainees.
The conflicting statements from the men who will be Trump’s most senior advisers increase uncertainty about what actions the new administration will take as military leaders continue to battle the Islamic State and grapple with growing challenges from China and North Korea.
Several hours after Mattis’s testimony before the Senate Armed Services Committee, the Senate voted 81 to 17 to waive a measure requiring defense secretaries to have been out of military service for seven years. Mattis retired in 2013.
Later in the day, the House Armed Services Committee approved a similar measure. The full House must also vote on that measure.
Although some of the president-elect’s other Cabinet picks have come under intense questioning in their own confirmation hearings, Mattis encountered virtually no challenges from lawmakers to his suitability for the top Pentagon job.
The 66-year-old veteran, known for his use of the call sign ‘‘Chaos’’ during overseas deployments, has earned a reputation as a scholarly, plain-spoken officer with an impressive combat record. His blunt style has brought controversy at times, as have his hawkish views on confronting threats in the Middle East.
Mattis was named the head of US Central Command in 2010, but he left in 2013 amid disagreement with the Obama White House over the general’s desire to intensify the military response to Iranian activities throughout the region.
Iran remains ‘‘the primary source of turmoil’’ in the Middle East, Mattis told lawmakers Thursday, with its support for regional militant cells, its ballistic missile capability, its maritime provocations, and cyberinitiatives.
Although Mattis’s hawkish views on the danger from Iran appear to coincide with Trump’s, he broke with the president-elect by voicing support for leaving the nuclear deal with Tehran intact.
‘‘I think it is in an imperfect arms control agreement — it’s not a friendship treaty,’’ he said. ‘‘But when America gives her word, we have to live up to it and work with our allies.’’
The questioning was notable for its scant discussion of the wars in Afghanistan, where 8,400 US troops are stationed; in Iraq, where about 6,000 Americans are supporting a punishing Iraqi offensive against the Islamic State; and in Syria, where a small Special Operations force hopes to help local forces drive the militants from their stronghold of Raqqa.
Mattis did say that the US strategy for Raqqa ‘‘needs to be reviewed and perhaps energized on a more aggressive timeline.’’
