WASHINGTON — President Trump was determined to leave his mark on Washington quickly. Now the city is leaving its bruising mark on him, with the same astonishing swiftness that has been a hallmark of his lightning-strike political career.

Mr. Trump has worn out opponents, journalists, members of Congress, foreign leaders, his staff — and now himself — with a breakneck barrage of executive actions, policy proposals and reversals, taunts, boasts and drowsy-hour Twitter assaults, all meant to disrupt American politics as usual.

But the president, who set a killing pace during his first four tumultuous months in office, has now been knocked off balance by an accelerating inquiry into possible collusion by his presidential campaign with Russia, as well as the backlash against his firing of the F.B.I. director who was leading the investigation.

Ten days of shocks, kicking off with Mr. Trump’s surprise ouster of James B. Comey on May 9 and continuing through the revelation on Friday that the president had called the F.B.I. chief a “nut job” in front of Russian officials, have left the West Wing reeling.