Early on, top aides wanted to restrain the president’s Twitter habit, even considering asking the company to impose a 15-minute delay on Mr. Trump’s messages. But 11,390 presidential tweets later, many administration officials and lawmakers embrace his Twitter obsession, flocking to his social media chief with suggestions. Policy meetings are hijacked when Mr. Trump gets an idea for a tweet, drawing in cabinet members and others for wordsmithing. And as a president often at war with his own bureaucracy, he deploys Twitter to break through logjams, overrule or humiliate recalcitrant advisers and pre-empt his staff…

More than half of the president’s posts — 5,889 — have been attacks; no other category even comes close. His targets include the Russia investigation, a Federal Reserve that won’t bow to his whims, previous administrations, entire cities that are led by Democrats, and adversaries from outspoken athletes to chief executives who displease him. Like no other modern president, Mr. Trump has publicly harangued businesses to advance his political goals and silence criticism, often with talk of government intervention. Using Twitter, he threatened “Saturday Night Live” with an investigation by the Federal Communications Commission and accused Amazon, led by Jeff Bezos, owner of The Washington Post, of cheating the United States Postal Service.

As much as anything, Twitter is the broadcast network for Mr. Trump’s parallel political reality — the “alternative facts” he has used to spread conspiracy theories, fake information and extremist content, including material that energizes some of his base.