WASHINGTON — As a political underdog and now as president-elect, Donald J. Trump has employed the same brutal but effective go-to move when he’s tweeted or talked himself into an impasse:

Attack the attacker.

That aggressiveness served him well in the presidential campaign, and allowed him to muscle through scandals and self-inflicted management mistakes that would have scuttled a lesser politician. But Mr. Trump’s postelection effort to minimize intelligence assessments about Russia’s actions came to an abrupt end Friday after a detailed classified briefing from the nation’s top intelligence officials at Trump Tower and the release of an unclassified report concluding that the Russian president, Vladimir V. Putin, had a “clear preference” for Mr. Trump.

By the end of the day, it was clear that the strategy of intimidation and bluster that served Mr. Trump so well in the presidential campaign would not prove nearly as effective in Washington. Here was a reminder, should Mr. Trump heed it, that a president’s critics, especially the lords of Washington’s national security establishment, can’t always be cowed by a flash-grenade tweet or a withering quip about the possibility that a “400-lb. hacker” might have breached Democratic servers.

“I don’t think what worked in a campaign against Jeb Bush is really going to work when you are dealing, you know, with the combined power of the C.I.A., N.S.A. and the F.B.I.,” said John Weaver, a frequent critic of Mr. Trump who worked on Ohio Gov. John Kasich’s unsuccessful primary campaign against him.

Senator Chuck Schumer, the New York Democrat who has a good working relationship with Mr. Trump, warned him recently that it was “really dumb” to take on the intelligence services. He followed up with a warning on Wednesday that the president-elect needed “to calm down” his Twitter usage.

He’s not alone. In recent days, Mr. Trump’s aides have gently prodded him to drop the attacks on the intelligence community and mollify nervous Republicans by showing that he was moving ahead with forward-looking reforms of the sprawling intelligence-gathering bureaucracy, according to two people close to the discussions. “He can’t afford this fight,” one longtime adviser to Mr. Trump said. “He’s said…