US President-elect Donald Trump says he will nominate retired General James Mattis to be his defence secretary, making the announcement during a post-election victory rally in Cincinnati.
General Mattis, 66, is a Marine Corps general who retired in 2013 after serving as the commander of the US Central Command.
The concerns revolve around whether a recently retired service member would rely more on military solutions to international problems, rather than a broader, more diplomatic approach.
For General Mattis to be confirmed, Congress would first have to approve legislation bypassing a law that bars retired military officers from becoming defence secretary within seven years of leaving active duty.
General Mattis has a reputation as a battle-hardened, tough-talking Marine who was entrusted with some of the most challenging commands in the US military.
In a tweet on Monday, Mr Trump referred to General Mattis by his nickname “Mad Dog”.
General Mattis would be only the second retired general to serve as defence secretary, the first being George C Marshall in 1950-51 during the Korean War.
“We are going to appoint ‘Mad Dog’ Mattis as our secretary of defence,” Mr Trump told a cheering crowd in Ohio.
“But we’re not announcing it until Monday, so don’t tell anyone. Mad Dog. He is great.”
General Marshall was a much different figure, having previously served as US secretary of state and playing a key role in creating closer ties with western Europe after World War II.
The only previous time an exception was made to the law barring someone from becoming defence secretary within seven years of leaving active duty was for General Marshall.
Although his record in combat and his credentials as a senior commander are widely admired, General Mattis has little experience in the diplomatic aspects of the job of a secretary of Defence.
Read more on abcnnews