WASHINGTON _ Donald Trump's pick of retired Marine Gen. James N. Mattis as secretary of defense has started a debate in Congress over civilian control of the military that will shadow his confirmation.
Mattis retired from the Marines in 2013 and federal law specifically bars anyone who served in uniform in the previous seven years from heading the Pentagon.
Congress would need to pass another law to grant Mattis a waiver _ the first since Congress agreed to let retired Army Gen. George C. Marshall become secretary of defense in 1950.
That law specifically warned against approving another recently retired military officer as a future Pentagon chief.
Republican leaders in Congress _ including Sen. John McCain of Arizona, who heads the Senate Armed Services Committee, and Rep. Mac Thornberry of Texas, who heads the House Armed Services Committee _ have indicated a willingness to grant Mattis the waiver.
But Democrats may not be so willing. At least one already has announced her opposition while others expressed concerns.
"While I deeply respect Gen. Mattis' service, I will oppose a waiver," said Sen. Kirsten Gillibrand, D-N.Y., ranking member on the Senate Armed Services subcommittee on personnel.
"Civilian control of our military is a fundamental principle of American democracy, and I will not vote for an exception to this rule," she said in a statement.
Trump's choice raises "serious questions about fundamental principles of our constitutional order," said Rep. Adam Smith, D-Wash., ranking member of the House Armed Services Committee.
"Civilian control of the military is not something to be casually cast aside," he said. "So while I like and respect Gen. Mattis a great deal, the House of Representatives would have to perform a full review, including hearings by the Armed Services Committee, if it were to consider overriding the statutory prohibition on recent military officers serving as the secretary of defense."
Congress should "bear in mind the precedent we would be setting and the impact it would have on the principle of civilian leadership of our nation's military," said Rep. Adam Schiff, D-Calif., ranking member of the House Intelligence Committee.
The 1947 federal law that created the Defense Department said military officers weren't allowed to head it within 10 years after their service ended. The ban was reduced to seven years in 2008.
While 18 of the 25 men confirmed as secretaries of defense since 1947 had previously served in the military, only Marshall had retired recently enough that he needed a waiver.
But Marshall's case was unique in many ways.
He agreed to accept the Pentagon post for just a year to help plan for the Korean War, which had just begun. He had already served as secretary of state for two years, and the rebuilding of Europe under the Marshall Plan ultimately would win him a Nobel Prize.
Moreover, except for a short staff assignment in France during World War I, Marshall was a headquarters general, not a combat commander.
As chief of staff of the Army during World War II, he oversaw the swift expansion of the U.S. military and coordinated Allied operations in Europe and the Pacific from his desk in Washington.
Mattis, who served four decades in the Marines, was more of a front-line officer. He served multiple combat tours in Iraq and Afghanistan.
Military officers traditionally stay outside the partisan political fray because they do not want their military advice to civilian leaders viewed as politically motivated.
Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, made sure he and his staff avoided articulating any opinion in public during the presidential campaign.
Mattis has been outspoken since retiring and has criticized some Obama administration policies, particularly on Iran.
Despite the concerns, Congress is expected to approve the waiver for Mattis and the Senate is then likely to confirm his nomination.
"I look forward to moving forward with the confirmation process as soon as possible in the new Congress," McCain said in a statement. "America will be fortunate to have Gen. Mattis in its service once again."
Thornberry called Mattis "an excellent selection" and pledged to "work with my colleagues in the coming days to clear the way for his confirmation by the Senate."
