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Story highlights

Mattis acquired the nickname "Mad Dog" after years as a leader in the military

Politicians have stepped up to defend President-elect Donald Trump's choice to lead the Pentagon

(CNN) —  

Retired Marine Gen. James Mattis addressed his “Mad Dog” nickname at his Senate confirmation hearing for defense secretary on Thursday.

“That nickname was given to me by the press, and some of you may have experienced similar occasions with the press where perhaps they didn’t get it quite right,” Mattis said during his testimony.

Mattis acquired the nickname “Mad Dog” – a moniker that is not used by people who know him, friends say – after he made comments such as “be polite, be professional, but have a plan to kill everybody you meet” and “a good soldier follows orders, but a true warrior wears his enemy’s skin like a poncho.”

The retired Marine general is well regarded by members of the US military and civilians alike. But his close ties with the military could pose an issue for his confirmation.

Section 903(a) of the National Defense Authorization Act requires a seven-year break from active duty before being eligible to serve as secretary of defense. Mattis would need a special waiver from Congress since he has only been retired for three.

Politicians have stepped up to defend President-elect Donald Trump’s choice, despite the potential break in protocol.

“I want to say he has the nickname of ‘Mad Dog’ – it’s a misnomer. It should be ‘Braveheart’ because what really characterizes Jim Mattis is his courage,” former Defense Secretary William Cohen said at the hearing Thursday morning. “Men and women in all services love this man.”

CNN’s Barbara Starr contributed to this report.