Sievert's post, on the locked personal account he shares among friends, was unusually partisan by the standards of corporate leaders who need to maintain relationships with both Republicans and Democrats. An image of the Facebook remarks taken shortly after Sievert posted them was shared with POLITICO.

The CEO, who also maintains public social media profiles with thousands of followers, declined to comment.

T-Mobile did not respond to a request for comment Wednesday. The company, based in Washington state and serving close to 100 million customers, is partly owned by Germany’s Deutsche Telekom and Japan’s SoftBank.

How we got here: Sievert, a longtime T-Mobile executive, succeeded John Legere as CEO on April 1, the same day the carrier completed its merger with Sprint. The pair had helped usher through the deal, originally valued at $26 billion, after announcing it in 2018.

Legere faced Democratic criticism during the merger approval process after T-Mobile spent $195,000 in stays for himself and fellow executives at the Trump International Hotel in Washington, D.C., sometimes shelling out more than $2,000 a room per night. (The executives included Sievert, then the company's chief operating officer and president.)

The hotel is near the headquarters of the Justice Department, which was reviewing the merger proposal. Democrats including Sen. Elizabeth Warren of Massachusetts and Rep. Pramila Jayapal of Washington state accused T-Mobile of trying to curry favor with the administration, while Republicans shrugged off the attacks and Legere insisted he was a longtime patron of Trump properties.

CEOs and politics: While many business leaders try to avoid alienating either political party, some executives make exceptions. Oracle co-founder Larry Ellison held a fundraiser for Trump in February, while Comcast executive David Cohen, who has been dialing back his corporate responsibilities this year, has emerged as a notable ally to Biden’s campaign.

Trump has obsessed over securing loyalty from American companies. He has called on customers to boycott corporations such as Goodyear, because of a ban on employees wearing "MAGA Attire," and AT&T, because of the way its network CNN covers him.

Sievert, meanwhile, has mainly kept quiet about his politics, although records tallied by the Center for Responsive Politics show 2016 and 2018 donations to Rep. Suzan DelBene (D-Wash.).

Sievert speaks up: His first five months as CEO have already included a spat with one of Trump’s favorite cable news hosts, Fox's Tucker Carlson, who warned viewers during a June segment about Black Lives Matter that the movement's supporters will "come for you.”

“Bye-bye Tucker Carlson!” Sievert tweeted, adding the hashtag Black Lives Matter and swearing off any T-Mobile advertising on the Fox program. (T-Mobile appears on a liberal watchdog group's list of companies that have stopped running ads on Carlson's show.)

His advice for Democrats: In the Facebook post, Sievert expressed sympathy with the goals of the Defund the Police movement, including a demand for more accountability for law enforcement officers and "better non-policing solutions" to social problems. He called himself “aghast” at the Aug. 23 shooting of Jacob Blake, an unarmed Black man, by Kenosha police.

However, the wrong message or tactics will only drive away moderate voters, Sievert wrote, drawing on his experience as a marketing expert.

“[I]f the mantra becomes ‘Defund the Police’ or worse, if we start to riot and tear down buildings or incite violence in response, the other guy wins. THE OTHER GUY WINS,” Sievert cautioned. “And the changes we want, and demand, don’t come about anytime soon."