The Auctioneer and the Treasury Chief: How Billy Long Fell Short at the I.R.S.

The meeting between Billy Long and President Trump in the gilded Oval Office last month was supposed to mark a victory for both men.

For Mr. Trump, the ceremonial swearing-in of Mr. Long to his role as the commissioner of the Internal Revenue Service underscored that he at last had a political loyalist and friend, rather than the typical technocrat, at the head of the powerful tax agency.

For Mr. Long, a former Republican congressman from Missouri, it signified the completion of a political comeback. After Mr. Long suffered a dismal showing in Missouri’s 2022 Republican Senate primary, his unwavering and, at times, over-the-top support for Mr. Trump had finally panned out.

As members of his family and close aides from his time in Congress looked on, he was put in charge of one of the federal government’s most visible and fundamental agencies, responsible for collecting roughly $5 trillion in tax revenue each year. By all appearances, Mr. Long had the full support of the president, who had also invited him to a private lunch that day and structured the July 18 swearing-in around it.

But within days, Mr. Long began to lose his grip on a job that he had held for barely a month. Treasury Secretary Scott Bessent had already ousted one White House-installed I.R.S. commissioner this year. He would soon orchestrate the removal of another, culminating in the agency having its seventh leader since January.

At the center of Mr. Bessent’s concerns was the fact that Mr. Long had been trying to put together an independent plan for the I.R.S. without informing the Treasury Department, according to five people familiar with the matter. But Mr. Long’s vision for the I.R.S. had at least in part been shaped by Mr. Trump.