President-elect Donald Trump kicked off his post-election "Thank You" tour Thursday by announcing that he would nominate retired Marine Gen. James Mattis as secretary of defense.

At a rally in Cincinnati, Trump described Mattis as "one of our great, great generals" and added that a formal announcement would be made Monday, "so don't tell anybody."

"They say he's the closest thing to Gen. George Patton that we have," Trump told the crowd, "and it's about time. It's about time."

A source close to Trump told Fox News that the president-elect's decision to divulge the Mattis pick at the rally was a surprise. Transition sources had repeatedly described Mattis as the favorite for the defense secretary position, but stressed the choice had not been formally made. Just prior to Thursday night's event, Trump himself played down the possibility that any announcement was imminent.

The 66-year-old Mattis, known by his nickname, "Mad Dog," retired from the military in 2013 after serving as the commander of the U.S. Central Command. His appointment to run the Pentagon would require a waiver from Congress, since federal law requires military personnel to be retired for seven years before taking a civilian position in the in the Department of Defense.

Senior staffers on the House and Senate Armed Services Committees told Fox News earlier this week that they had already drawn up language for the required waiver and were ready to present it to Congress if Trump nominated Mattis quickly.

Mattis would be only the second retired general to serve as defense secretary, the first being George C. Marshall in 1950-51 during the Korean War. Marshall was a much different figure, having previously served as U.S. 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 defense secretary within seven years of leaving active duty was for Marshall.



Although his record in combat and his credentials as a senior commander are widely admired, Mattis has little experience in the diplomatic aspects of the job of a secretary of defense.



Richard Fontaine, president of the Center for a New American Security, described Mattis as a defense intellectual and as a military leader who distinguished himself in combat.



"He knows the Middle East, South Asia, NATO and other areas and has evinced both a nuanced approach to the wars we're in and an appreciation for the importance of allies," Fontaine told the Associated Press in an email. "If he were to get the nomination, I suspect that he could attract a number of very talented people to work with him."



But Mattis hasn't been immune to controversy. At a 2005 forum in San Diego, he told his audience that "it's a lot of fun to fight. You know, it's a hell of a hoot. ... It's fun to shoot some people. I'll be right up front with you, I like brawling."



"You go into Afghanistan, you got guys who slap women around for five years because they didn't wear a veil," Mattis continued. "You know, guys like that ain't got no manhood left anyway. So it's a hell of a lot of fun to shoot them."

A native of Pullman, Wash., Mattis enlisted in the Marine Corps in 1969, later earning a history degree from Central Washington University. He was commissioned as an officer in 1972. As a lieutenant colonel, Mattis led an assault battalion into Kuwait during the first U.S. war with Iraq in 1991.



As head of the Central Command from 2010 until his retirement in 2013, he was in charge of both the wars in Iraq and Afghanistan.



In the aftermath of the 9/11 attacks, Mattis commanded the Marines who launched an early amphibious assault into Afghanistan and established a U.S. foothold in the Taliban heartland.



As the first wave of Marines moved toward Kandahar, Mattis declared that, "The Marines have landed, and now we own a piece of Afghanistan."



Two years later, he helped lead the invasion into Iraq in 2003 as the two-star commander of the 1st Marine Division.

The rest of the rally at Cincinnati's U.S. Bank Arena was a return to Trump's campaign roots. He took a veiled swipe at fellow Republicans. He remembered his general election foe by joking, "We had fun fighting Hillary, didn't we?" He boasted about size of his victory and repeatedly bashed the media. Protesters briefly interrupted the proceedings. And the crowd chanted "Build the Wall" and "Lock Her Up."

Trump did nothing to downplay expectations before he takes office, declaring that "America will start winning again, big league." Much like he did during the stretch run of the campaign, he read from teleprompters, but he was bombastic as ever, spending more than a dozen minutes bragging about his victory before outlining his economic plan.

He boasted about his wins in Midwest states that normally vote Democratic, declaring he didn't just "break the blue wall, we shattered it." He veered off-script to make fun of a protester, saying she was being ejected from the arena so "she could go back to Mommy." He repeated his recent threat that, despite Constitutional protections, "if people burn the American flag, there should be consequences." And he repeated many of his signature campaign promises, including a pledge to "construct a great wall at the border."

Trump, who has long spoken of feeding off the energy of his raucous crowds, first floated the idea of a victory tour just days after winning the election but has instead prioritized filling Cabinet positions. He is also expected to hold rallies in Pennsylvania, Florida, North Carolina and Michigan in the coming weeks, though details have yet to be announced. His supporters were thrilled that he had hit the road again.

"That he wants to do this, to take time out of his schedule to fly out here and personally thank the people ... shows what kind of man he is," said Josh Kanowitz, 43. "He's one of us."

But while Kanowitz largely praised Trump's initial moves as president-elect, he visibly recoiled at the suggestion that he might pick Mitt Romney as secretary of state, saying the 2012 Republican presidential nominee was "someone we should leave behind as we move forward."

Others at the rally also expressed some hesitancy at Trump's picks, with a few suggesting that choosing former Goldman Sachs partner Steven Mnuchin as Treasury Secretary was not exactly fulfilling Trump's campaign promise to "Drain the Swamp" and eliminate corruption and elitism from Washington.

But most were inclined to give the president-elect the benefit of the doubt.

"He's a businessman. He'll pick talented people to work for him and then keep them in line," said Jaime Bollmer, a 28-year-old teacher from Lockland, Ohio. "He's a leader. That's what leaders do."

Earlier Thursday, Trump and Vice President-elect Mike Pence toured a Carrier plant in Indiana to tout the incoming administration's agreement with the air conditioning manufacturer to keep hundreds of jobs in the U.S.

"Companies are not going to leave the United States anymore without consequences," Trump thundered, before tempering the threat with pledges for deregulation and lower taxes.

"We're going to do great things for businesses," Trump said. "There's no reason for them to leave anymore."

Trump threatened to impose sharp tariffs on any company that shifted its factories to Mexico. And his advisers have since promoted lower corporate tax rates as a means of keeping jobs in the U.S.

Fox News' John Roberts and Jennifer Griffin contributed to this report. The Associated Press also contributed to this report.