In Donald Trump’s White House, Reince Priebus and Sean Spicer were more than chief of staff and press secretary. They were the president’s connection to the Washington establishment: the donors, flacks and apparatchiks of both parties whose influence over politics and the economy many Trump supporters wish to upend.

By firing Mr. Priebus and Mr. Spicer and hiring John Kelly and Anthony Scaramucci, President Trump has sent a message: After six months of trying to behave like a conventional Republican president, he’s done. His opponents now include not only the Democrats, but the elites of both political parties.

Since the start of his presidential campaign, Mr. Trump has made no secret of his dislike of the capital. But his contempt for the city and the officials, lobbyists, consultants, strategists, lawyers, journalists, wonks, soldiers, bureaucrats, educators and physicians who populate it becomes more acute with each passing day.

He ignores pleas to ratchet back his Twitter feed, rails against the inability of Congress to advance his agenda, bashes the press, accuses the so-called deep state of bureaucratic setbacks, and struggles to hire staff. In Robert Mueller, the special counsel, he faces a paragon of D.C. officialdom, investigating not only his campaign but also perhaps his finances. For Trump, the Senate’s failure to repeal Obamacare was more evidence of Washington dysfunction, and a reason to declare independence from Priebus, the Republicans and political norms. The call to “drain the swamp” is now a declaration of war against all that threatens his presidency.