But some intelligence officials said Ms. Pierson did not say that the current interference was explicitly on Mr. Trump’s behalf. Others in the briefing said that in response to lawmakers’ follow-up questions, officials made the connection between the Russian preference for Mr. Trump and Moscow’s efforts to interfere in the election.
The difference between actively backing Mr. Trump and preferring his re-election is a subtle nuance, officials say, but an important one: It is probably too early for the Russians to begin any significant move to bolster a specific candidate. In 2016, they at first sought to cause chaos and hurt Hillary Clinton, intelligence reports released later that year said, but only in the last few months before the election did they actively work to elect Mr. Trump.
If they go the same route now, it would not be inconsistent with backing Mr. Sanders for the Democratic nomination, in part because Mr. Sanders has voted against new sanctions on Russia and because he is considered a noninterventionist. And they may conclude, rightly or wrongly, that Mr. Trump could beat Mr. Sanders.
Mr. O’Brien seemed to have little doubt that the Russians preferred Mr. Sanders. “What I’ve heard from the F.B.I.,” he said, “is that Russia would like Bernie Sanders to win the Democrat nomination. They’d probably like him to be president, understandably, because he wants to spend money on social programs and probably would have to take it out of the military.”
He did not give the source of that intelligence.
Mr. Sanders has denounced Russia and warned it not to interfere in the election.
Mr. Biden, who was in office as the Obama White House struggled over how to respond to Russian interference in 2016, saw some advantage in claiming he was the candidate Mr. Putin hated.
“The Russians don’t want me to be the nominee,” he said on “Face the Nation.” “They spent a lot of money on bots on Facebook, and they’ve been taken down, saying Biden is a bad guy. They don’t want Biden running. They’re not — no one’s helping me to try to get the nomination. They have good reason.”