The federal prosecutor whom Mr. Barr appointed to review the government’s response to Russian election interference, John H. Durham, is examining whether the C.I.A. or other intelligence agencies overstated President Vladimir V. Putin’s support of the Trump campaign, a central finding of the 2017 assessment. His team has interviewed intelligence analysts, questioning whether Obama-era intelligence officials hid evidence or manipulated analysis about Moscow’s covert operation, people familiar with the Durham inquiry have said.

Some of Mr. Trump’s allies immediately criticized the Senate report; Fred Fleitz, a former C.I.A. officer who briefly served in the Trump administration, dismissed it as “a whitewash.” Many Republicans believe that the intelligence agencies overstated Russia’s support for Mr. Trump and argue that Moscow was trying to sow chaos in the United States, not support any one candidate.

The report released Tuesday was the latest installment in an inquiry by the Senate Intelligence Committee into the broader Russia matter. Senators are expected to release one final chapter in the coming months examining contacts between the Trump campaign and Russia.

When the inquiry began in early 2017, it was one of the most closely followed in the history of Congress, casting a cloud over Mr. Trump’s presidency that could not be dismissed as merely partisan. But with the investigation into the same topic by the special counsel, Robert S. Mueller III, long since put to rest; an impeachment fight over a largely unrelated matter behind the country; and a pandemic reshaping nearly every aspect of life, the Russia inquiry has now largely become an afterthought for most Americans.

The Senate Intelligence Committee had already given the work of the C.I.A. and the F.B.I. an interim stamp of approval, but the 158-page report released on Tuesday presented new detail about the government’s attempts in late 2016 and early 2017 to make sense of Russia’s attacks. Much of the report’s contents were considered highly sensitive and blacked out by the Trump administration before release.