The report provides no new evidence to support assertions that Moscow meddled covertly through hacking and other actions to boost the electoral chances of Donald J. Trump and undermine his rival, Hillary Clinton, but rests instead on what it describes as Moscow’s long record of trying to influence America’s political system.

“Russia, like its Soviet predecessor, has a history of conducting covert influence campaigns focused on U.S. presidential elections that have used intelligence officers and agents and press placements to disparage candidates perceived as hostile to the Kremlin,” the report said. This campaign, it said, blended covert activities like hacking with public action by “Russian government agencies, state-funded media, third-party intermediaries and paid social media users or ‘trolls.’ ”

The public report did not include evidence on the sources and methods used to collect the information about Mr. Putin and his associates that intelligence officials said was in a classified version.

Mark Galeotti, an expert on Russian intelligence agencies at the Institute of International Relations in Prague, said he was skeptical of the accusation that Mr. Putin had ordered the hacking. All the same, he added, Russian spies, like their Soviet predecessors, “don’t just collect information but try to assert influence.” United States intelligence operatives, he said, have often done the same thing but the Russians, convinced that the United States orchestrated protests in Ukraine in 2014 that toppled the pro-Moscow president, Viktor F. Yanukovych, and other popular uprisings in former Soviet lands, “have a more aggressive approach to meddling in other people’s politics.”

Particularly since Mr. Yanukovych lost power after protests in Maidan Square in Kiev, Mr. Galeotti said, Mr. Putin and his circle “have a different sense of how the game is played. They genuinely believe that Maidan was engineered by the West” and because of this “all bets are off” in their view, a shift that has legitimized “the principle of regime change or at least regime disturbance” through mischief making in the United States election.

That Russia considers it possible to influence United States elections has been evident since at least 1968 when, according to Moscow’s former longtime ambassador in Washington, Anatoly Dobrynin, the Kremlin decided that Richard M. Nixon was “profoundly anti-Soviet” and must be prevented if possible from winning the presidency. Mr. Dobrynin, in his 1995 memoir “In Confidence,” said he was ordered by Moscow to offer Mr. Nixon’s Democratic rival, Hubert H. Humphrey Jr., “any conceivable help in his election campaign — including financial aid.”

Mr. Dobrynin related in his memoir how he thought this was a bad idea but nonetheless made an oblique offer of help to Mr. Humphrey during a breakfast at the Democratic candidate’s home. “He knew at once what was going on,” Mr. Dobrynin recalled, and made it clear he had no interest in receiving any Soviet assistance.