Secretary of Defense James Mattis recalled in a press conference on Aug. 31 how he was hired by President Donald Trump.
After serving for 44 years in the Marine Corps, and having retired in 2013, Mattis was called on by the president to serve.
"When a president of the United States asks you to do something, I come—I don't think it's an old-fashioned school at all. I don't think it's old-fashioned or anything," Mattis said.
Mattis was asked by a reporter at a press briefing how he dealt with the frequent calls from critics of the president for his senior staff, such as Mattis, White House Chief of Staff Gen. John Kelly, and National Security Adviser Gen. H.R. McMaster, to resign.
"I don't care if it's Republican or Democrat, we all have an obligation to serve. That's all there is to it," Mattis said.
Recalling his interview with President Trump, Mattis spoke to the fact that the president is open to change his mind based on good arguments.
"The first time I met with President Trump, we disagreed on three things in my first 40 minutes with him, on NATO, on torture, and something else, and he hired me. This is not a man who's immune to being persuaded," Mattis said.
Other politicians have said the same about Trump.
Canadian Prime Minister Justin Trudeau said in April this year that he had learned that "unlike many other politicians" Trump actually listens.
"As politicians we are very very much trained to say something and stick with it, whereas he has shown that if he says one thing and then actually hears good counter-arguments or reasons why he should shift his position he will take a different position if it's a better one, if the arguments win him over," Trudeau told Bloomberg in April.
Mattis, also known as "Mad Dog" and "Warrior Monk," earned a reputation over the years for speaking his mind and meaning what he says.
Over his years in the Corps, Mattis won deep admiration among the men and women who served under him.
"He was the kind of guy who was on the ground with the troops, and that's why they liked him so much," said long-time army combat veteran and former intelligence official Mike Furlong in an interview with The Epoch Times in December last year.
Mattis preferred a firsthand understanding of the wars and would often go to the front lines to experience the battle directly.
He is noted for having a personal library of more than 7,000 books and an extensive interest in military history and world history.
Among the military's intellectual class, Mattis is known as the "Warrior Monk" for his study of classic books and military thought. Also, he never married, and instead dedicated his life to the Marine Corps.
"He gets himself out of the morass," Furlong said. "Here's a guy with his character, who steps back at night and thinks of ways to think out of the box to get things done."
Mattis didn't necessarily like being called "Mad Dog," but he appreciated it, since the nickname was given to him by the troops on the front lines. His call sign was "Chaos."