For years, President Trump has offered a hodgepodge of conspiracy theories and baseless charges to support his falsehood that the 2020 election was stolen from him, and that America’s election system was hijacked by a combination of outside powers and “deep state” insiders.

But when he declassified a raft of intelligence reports, hastily drafted emails between officials at the F.B.I. and other agencies, and formal “assessments” late Thursday, he was unable to prove his case.

An examination of the more than 270 pages of evidence released by the White House supports the broad conclusions already announced in 2020 and 2021, albeit with some finer details. For example, China considered modest attempts to influence opinion in the United States, and downloaded publicly available voter rolls from several states, but never manipulated a single voting machine or ballot.

Even new assertions, such as a document from the Department of Homeland Security claiming to have found more than 250,000 noncitizens registered in California, New Jersey, Nevada and Pennsylvania, came devoid of supporting evidence and immediate was met with pushback from state officials.

In the end, the documentary evidence that Mr. Trump promised appeared bound to disappoint those who expected bombshell revelations, not unlike the Pentagon’s release of “never-before-seen” reports of unidentified flying objects and the last government documents about the Kennedy assassination.

Still, the trove was completely consistent with the recollections of the nation’s intelligence leadership at the time. “There were certainly nations that wanted to influence parts of the election,” said Timothy Haugh, a retired four-star general who was deeply involved in the efforts by intelligence agencies to secure elections from 2018 through 2024. (He was fired last year by Mr. Trump, for unspecified reasons, as the director of the National Security Agency and the commander of United States Cyber Command.)

But, he added at the Aspen Security Forum on Thursday afternoon, just hours before the documents were released, “we had no areas that brought us to a concern of an impact” on voting results. The newly released documents affirmed that, as countless investigations, state audits and lawsuits had already firmly established.

Even Mr. Trump, in his 25-minute address to the nation, did not argue that the documents proved he won the election. The closest he came was when he said “our elections were left vulnerable, to being rigged and stolen, and the trust of the American people was lost,” lines that have already become a common refrain on the campaign trail and in conversations with reporters.

He did argue that those “vulnerabilities” needed to be patched, a point that election experts have made for years. But it runs contrary to his actions: Fixing the holes in the system, and testing election machines, is exactly what the Cybersecurity and Infrastructure Security Agency was doing, before he eviscerated it last year and referred its former director, Christopher Krebs, who had declared the 2020 election secure, to the Justice Department for investigation. No charges have been filed.

That was only the beginning of the contradictions in Mr. Trump’s effort to make his case. The reports he personally declassified — some on July 3, just before he led some of the celebrations of the 250th anniversary of the signing of the Declaration of Independence — are laced with references to Russia’s efforts to influence voters, too. But Mr. Trump only mentioned Russia once during his speech, and then in passing, quoting an intelligence assessment.

His description of China’s efforts to obtain information about voters omitted the fact that most of the data was publicly available, sometimes for a fee. In short, it did not appear that the Chinese had infiltrated the voting databases the way they have hacked America’s telecom networks, its defense industrial base or its power grid.

And in giving the speech, Mr. Trump had to navigate one inconvenient element of the evidence: Many of the documents he published, especially about China, were compiled during his first term. That raised the question of why he did not act then.

His answer was that the intelligence briefers deprived him of key information.

“Everything was kept out that was of importance,” he argued, citing one email that referred to how information for the presidential daily brief was “deliberately massaged.” What he failed to mention was that at the time that memo was written, his director of national intelligence was John Ratcliffe, who served in the post from May 2020 through the end of Mr. Trump’s first term in January 2021. He is now his C.I.A. chief.

Mr. Ratcliffe was not among the cabinet members and aides who sat quietly in the East Room as Mr. Trump addressed the nation, according to a White House pool report.

But the trove of documents released by the administration offered a much fuller — though still incomplete, because of heavy redactions — picture than has previously been available about China’s long-running efforts to understand, and potentially try to influence, voters with propaganda. One newly released C.I.A. document was titled “Sensitive PRC reporting from 2018-2020,” suggesting it may have been written after President Joseph R. Biden Jr. was inaugurated on Jan. 20, 2021. (The date of the document appears to have been redacted.)

“In mid 2018 the Chinese Communist Party’s policy was to leverage all domestic and foreign elements that were opposed to the U.S. president,” it reads, “in an effort to reduce the U.S. president’s votes and make him resign or prevent his re-election.”

Mr. Trump’s release of the document appears to signal he believes that effort may still be underway. It was only in May, visiting Beijing, that Mr. Trump referred to China as a partner, talked about it in far more glowing terms than he does European allies, and told President Xi Jinping that the two superpowers would have a “fantastic future together.”