The report also hinted at some intriguing new findings — but their effect was muted by the scope of the deletions demanded by intelligence agencies. For example, the report noted that the State Department was aware that Russian officials had requested to send election observers to polling places in the 2016 election — just as the United States often seeks to send observers to elections in foreign nations, including Russia.

That was of concern to the committee because testimony about election machines, which are disconnected from the internet, suggested the most efficient way to alter votes was with physical access to the machines or computers rather than programming them with ballots.

Given the potential for further incursions into the election system, the move by the intelligence agencies to redact large portions of the public version of the report touched off behind-the-scenes battles with members of the committee.

The deletions were so substantial that even the committee’s recommendations for the future were not spared: The section heading on the final recommendation read “Build a Credible,” but the remainder of the heading, and two paragraphs that follow, were blacked out.

The report, black lines and all, is titled, “Russian Efforts Against Election Infrastructure.” It is the first volume the committee has publicly released, after more than 200 witness interviews and the collection and review of nearly 400,000 documents. Subsequent volumes will deal with Russia’s effort to use social media to influence voters — an area where Russian interference may have changed minds, and thus votes — and the 200 or so contacts between Russia and members of the Trump campaign.

In a statement, Senator Richard M. Burr, Republican of North Carolina and the chairman of the committee, described the events of 2016 as one in which the United States was blindsided.

“In 2016, the U.S. was unprepared at all levels of government for a concerted attack from a determined foreign adversary on our election infrastructure,” Mr. Burr wrote. “Since then, we have learned much more about the nature of Russia’s cyberactivities and better understand the real and urgent threat they pose.”