After agitating for weeks over ways to make Amazon pay higher postage rates, Donald Trump has demanded a sweeping overhaul of the U.S. Postal Service’s business model. In an executive order Thursday, Trump called for the formation of an administration task force to be chaired by Treasury Secretary Steve Mnuchin, with a report outlining proposed changes delivered within 120 days. “A number of factors, including the steep decline in First-Class Mail volume, coupled with legal mandates that compel the U.S.P.S. to incur substantial and inflexible costs, have resulted in a structural deficit,” Trump said. “The U.S.P.S. is on an unsustainable financial path and must be re-structured to prevent a taxpayer-funded bailout.”

Trump didn’t mention Amazon by name, but it’s clear who the order is intended to punish. “He’s off the hook on this. It’s war,” one source close the White House told my colleague Gabriel Sherman last week, describing the president’s fulminations against the e-commerce giant and its billionaire owner, Jeff Bezos, the wealthiest man in the world. “He gets obsessed with something, and now he’s obsessed with Bezos,” said another source. “Trump is like, how can I fuck with him?”

Outwardly, the president has framed his enmity toward Amazon as a defense of the Post Office, raging on Twitter about the “many billions of dollars a year” the U.S.P.S. supposedly loses for “being their Delivery Boy”—a situation he says puts “many thousands of retailers out of business.” The obsession isn't shared by aides: despite Trump’s repeated claims, his own advisers have said that the sheer volume of packages Amazon ships through the Postal Service has helped keep it afloat. Amazon and the Postal Service signed a five-year deal in 2013 to deliver packages on Sundays, and both entities have declared the arrangement a success.

Behind closed doors, however, White House insiders describe the Amazon-U.S.P.S blowup as a thinly veiled attempt to retaliate against The Washington Post, which Bezos owns, for its frequently critical coverage of his administration:

“Trump doesn’t like The New York Times, but he reveres it because it’s his hometown paper. The Washington Post, he has zero respect for,” the Republican close to the White House said. While the Post says that Bezos has no involvement in newsroom decisions, Trump has told advisers he believes Bezos uses the paper as a political weapon. One former White House official said Trump looks at the Post the same way he looks at The National Enquirer. “When Bezos says he has no involvement, Trump doesn’t believe him. His experience is with the David Peckers of the world. Whether it’s right or wrong, he knows it can be done.”

Trump, who has called the Post Amazon’s “chief lobbyist,” has several ways he could hurt Bezos, if he decides to push his tin-pot-dictator instincts to their limit: nine seats on the Postal Service’s governing board have been vacant since 2016. While the Postal Service’s board isn’t directly involved in negotiating contracts like the one that exists between Amazon and the U.S.P.S., it does consult with Congress on laws that could improve how its business operates. Another potential opportunity for hurting Amazon: giving a multi-billion-dollar Defense Department cloud-computing contract to a competitor, as some of the president’s advisers have encouraged him to do. Earlier this month, Trump met with Oracle chief executive Safra Catz, stoking speculation that Trump was boosting a rival for a contract that Amazon otherwise seemed likely to win.