Defense Secretary Jim Mattis is not considering a run for president, and certainly not saying that if he did run, he’d “kick Trump’s ass,” the Pentagon said Thursday.

“We got quite a laugh out of it in our morning meeting. It’s pure fiction — plain and simple," said Pentagon press secretary Dana White.

The latest Mattis 2020 rumor was published by Beltway Breakfast, an online publication that was previously focused on reporting on broadband technology. In the piece, a reporter said the ass-kicking comment came about as Mattis and other military officials discussed the possibility that the defense secretary would be asked by President Donald Trump to step aside.

Mattis is one of the longest-serving members of Trump’s cabinet, although recent White House-led announcements, where it appeared the Pentagon was not consulted, have lead to speculation that he was on the way out.

Among some of the more alliance-shifting moves made by President Trump, such as recent overtures to both Russia and North Korea, Mattis has responded by emphasizing a steady path forward and taken great pains to not be trapped into any public comments that might be construed as differences in opinion between Trump and himself on national security.

President Donald Trump selected retired Marine Gen. Jim Mattis as his secretary of defense. With Republicans in charge of Congress, a priority of the new team is to boost the military budget by tens of billions of dollars. The administration has also loosened the rules of engagement and increased the number of U.S. troops in Afghanistan. (Susan Walsh/AP)
President Donald Trump selected retired Marine Gen. Jim Mattis as his secretary of defense. With Republicans in charge of Congress, a priority of the new team is to boost the military budget by tens of billions of dollars. The administration has also loosened the rules of engagement and increased the number of U.S. troops in Afghanistan. (Susan Walsh/AP)

It’s not the first time Mattis' name has been suggested for the White House. TIME magazine wondered in spring of 2016 whether he’d run, and opined on America’s public trust in its generals.

The retired four-star general has inspired a cult-like following online, with Mattis T-shirts, “Saint Mattis” candles, even Mattis .50 caliber bullet bottle openers. Insiders who have worked closely with him in this administration however, have unanimously said Mattis has no interest in the higher office, and said he seeks to serve the entire four years, to have enough time to carry out his vision for personnel, strategy and resourcing across the department.

Mattis was asked by Pentagon reporters in late December whether he thought he would remain defense secretary for the entire first term.

“I take it one day at a time,” he said.

For comparison, Mattis' three most recent predecessors in the position, secretaries Leon Panetta, Chuck Hagel and Ash Carter, each served about two years or less.