Less than a month ago, Jason Chaffetz, the Republican chairman of the House Oversight Committee, told The Atlantic’s McKay Coppins that he expected to retain his powerful position on Capitol Hill for the foreseeable future. “You can be the chairman up to six years,” he said, having assumed the chairmanship in 2015. But this week, Chaffetz seemed to have an abrupt change of heart. On Wednesday, the Utah congressman announced on Facebook that he would not run for re-election in 2018. He said he has “no ulterior motives” for abandoning his political career, but did not specify why he would be stepping down. “I am healthy. I am confident I would continue to be re-elected by large margins. I have the full support of Speaker Ryan to continue as Chairman of the Oversight and Government Reform Committee,” he wrote. “That said, I have made a personal decision to return to the private sector.”

In a city where few people willingly relinquish power for any reason, Chaffetz’s announcement was met with a mix of confusion, delight, and no small amount of alarm that something sinister could be afoot. Things got murkier on Thursday, when he told KSL Newsradio that he “might depart early,” resigning before the end of his term.

Speculation swirled as to whether Chaffetz had gotten a television job offer, or whether a scandal was brewing. (Louise Mensch tweeted that she had heard the Russians had kompromat on the squeaky-clean Mormon.) On Friday, a lengthy profile in Utah's Deseret News, which Chaffetz participated in, reported that the 50-year-old father of three was tired of being away from his family. It also suggested that after spending much of the last year giddily preparing to use his perch as Oversight chairman to torment Hillary Clinton, Chaffetz found himself unprepared to face the thousands of angry constituents demanding that he apply that same energy to investigating Donald Trump.

Chaffetz himself gave several explanations for his premature exit to the Deseret News, and hinted at others reasons too. He wants to make more money in the private sector, he suggested, and possibly pursue a media career. His wife, Julie, was starting to feel the strain of his public life, he said, which now includes death threats. (Chaffetz recently tweeted a Heavy.com article that praised Julie’s steadfast devotion to him.) Others speculated that he was stepping down to pursue an even higher office—possibly Senator or Governor—and that now might be the best time for Chaffetz to take a break from politics before the Republican Congress gets dragged down by Trump. “My guess is he wants to start rebuilding a base for (governor) in 2020,” a Utah political heavyweight told the Deseret News. “No member of Congress has been elected Utah governor in recent years—maybe ever—though many have tried. His P.R. instincts probably tell him that he can't be seen as coming straight from Congress, therefore some distancing before things get serious.”

Chaffetz may have even higher ambitions, too: on Thursday, Fusion reported that campaign committee Friends of Jason Chaffetz recently registered Jason2028.com and JasonChaffetz2028.com, hinting at a potential presidential run in 12 years’ time.

As mysterious as Chaffetz’s personal motivations may be, the political calculus is even more perplexing. The Deseret News notes that Chaffetz’s support for the G.O.P.’s unpopular health-care bill and statements suggesting he saw no reason to investigate President Trump had caused his approval rating to drop a staggering 14 points. Thousands of protesters targeted one of his recent town-hall events, and thousands of dollars are pouring into a potential Democratic challenger in 2018. “For the first time since his election, Chaffetz would actually have to campaign and spend a good chunk of the next year aggressively fundraising, a chore he’s never enjoyed,” wrote The Deseret News. “The campaign could get costly, loud and bruising. And for someone who had much greater ambitions than the House, it could do lasting damage to his brand.” At the same time, however, there is almost no chance that Chaffetz would actually lose his seat in such a deep-red district: in 2016, he won by about 46 points—a virtually insurmountable advantage.

There is also the possibility that Chaffetz may be resigning early in order to actually do his job—which includes investigating the president—without sticking around to suffer the blowback. Later on Friday, the House Oversight Committee released a letter demanding that the Trump Organization hand over any documents related to the company’s revenues from foreign governments at Trump properties, and whether Trump himself had donated those profits to the U.S. Treasury as promised. That could put him in the cross hairs of his fellow Republicans, who expect their Oversight chairman to go easy on the president. “Your job is to over-investigate when the other party is in power and under-investigate when your party is in power,” said Tom Davis himself a former chairman of the committee.

This article has been updated to remove a description of Louise Mensch as a left-wing reporter.