The White House in recent weeks has made public a steady drip of previously classified intelligence about foreign threats to elections and other matters, offering President Trump and his allies ammunition for baseless conspiracy theories about potential vote rigging.

But one crucial document has not been among the releases, despite a congressional requirement for it to be: the assessment by U.S. intelligence agencies of foreign meddling efforts during the 2024 election.

The document would provide the public with a holistic look at foreign attempts to influence voters and sow division around the presidential contest and other federal races that year. The 2020 version of the assessment, released during the early weeks of the Biden administration, highlighted Russia’s efforts to boost Mr. Trump, Iran’s push to harm his candidacy and analytic judgments about actions China considered but largely refrained from taking. It also included a dissenting minority view that China took “at least some steps” intended to undermine Mr. Trump.

The omission of the report on the 2024 election shows the highly selective nature of the Trump White House’s approach to declassification. It is just one example of many where the administration has ignored bipartisan pressure from Congress, including legal requirements, by withholding certain documents from public view even as it publishes hundreds of pages of material it has promised will reveal deep-state coverups of foreign meddling efforts.

“While the president and his intelligence leaders have broad authority to declassify and release publicly classified information, any decision to do so needs to meet the public interest while also weighing very carefully the risk to sources and methods,” said Larry Pfeiffer, a former senior intelligence official at the C.I.A. and National Security Agency who was involved in classification decisions throughout his decades-long career, including during the George W. Bush and Obama administrations. “Refusals to do so need to meet the same balancing test.”

Picking and choosing what intelligence to disclose is the prerogative of any president, a tradition presidents have observed since the modern classification system was established during the Truman and Eisenhower administrations. But Mr. Trump has politically weaponized that system like never before during his second term, Mr. Pfeiffer said, adding that the president’s declassification decisions had “gone largely unchecked while appearing to be driven primarily by political and revenge agendas.”

The administration has not publicly explained why the 2024 file has not been released, even as Mr. Trump has vowed in recent weeks to protect elections from foreign and domestic threats. As part of that effort, he designated his ally, the conservative journalist John Solomon, as a special government employee responsible for overseeing the declassification of intelligence reports related to election integrity, among other matters.

During a prime-time speech last month previewing the releases, the president said he would make public intelligence “revealing shocking vulnerabilities in our election infrastructure” and claimed, with scant evidence, that U.S. officials had engaged in a “coverup” to hide the extent of China’s efforts to influence American elections. The heavily redacted documents did not reveal major new weaknesses in the country’s election systems or show that foreign governments had manipulated any votes.

In essence, the releases have centered on material that rehashes information made public years ago about the 2020 election, which Mr. Trump lost, while shielding from public view new information about the 2024 election, which Mr. Trump won. The White House declined to answer specific questions about its declassification process, but a spokesman suggested the transparency task force behind the effort was only getting started. He added: “Stay tuned!”

Disclosures during the Biden administration, including federal indictments, accused both Russia and Iran of engaging in aggressive influence operations in 2024. Iranians were charged with hacking Mr. Trump’s campaign and shopping stolen material to various news outlets in an effort to harm his bid to return to the White House. The Justice Department and other agencies accused President Vladimir V. Putin of Russia of again trying to bolster Mr. Trump (and degrade U.S. support for Ukraine) by targeting the United States with disinformation — including by secretly funneling $10 million to a conservative media start-up.

But those revelations were piecemeal, and do not offer a full portrait of what foreign meddling took place.

Congress passed a number of laws after Russia’s interference in the 2016 presidential election intended to better inoculate the American public from foreign attempts to influence voters. That included requirements for more transparency with lawmakers and the public from the nation’s spy agencies about what intelligence had been collected concerning the ambitions of foreign powers around federal elections.

In a letter in July, Democrats on the House Intelligence Committee urged Bill Pulte, then the acting director of national intelligence, to declassify and publicly release a redacted version of the 2024 election report. The law at issue requires the assessment’s public release within 60 days of the conclusion of the federal election cycle “to the greatest extent possible” while protecting sources and methods.

The Trump administration also has yet to deliver to Congress a report required by law, identifying foreign intelligence threats to the coming 2026 midterm election. The deadline was in early May, a Democratic aide to the House Intelligence Committee said.

“The intelligence community is currently in violation of multiple statutes designed to ensure that Congress understands the full scope of foreign adversary plans and intentions this cycle,” as well as the administration’s efforts to combat those threats, the letter said.

In an effort to pressure the Trump administration on the matter, the intelligence panel recently passed an amendment written by Representative Jason Crow, a Colorado Democrat, that would partly withhold funding from the Office of the Director of National Intelligence until Congress receives the report. The language was attached to the annual intelligence authorization bill, must-pass legislation that remains pending in Congress.

The Trump administration has invoked the classification justification in other instances. The Pentagon declined to release the full video of a lethal strike in September on a boat ferrying suspected drug smugglers in the Caribbean. Drone footage showed the vessel being struck by a U.S. missile that left two shipwrecked survivors, only for a second missile strike to kill them.

Despite calls for the video’s release from Democrats and some Republicans on Capitol Hill, Defense Secretary Pete Hegseth argued that it was top secret, even as the Pentagon published numerous video snippets on social media of its counterdrug strikes.

And in the spring, the bipartisan leaders of the Senate Intelligence Committee urged O.D.N.I. to release a classified court ruling in March from the secretive Foreign Intelligence Surveillance Court as part of a deal securing a short-term extension of a powerful spying law. The ruling, which is said to have admonished U.S. intelligence agencies over how they analyze certain intercepted communications, remains classified.

To some degree, presidents in both parties have always leaned on their declassification powers to selectively release files while holding back other secrets that could be considered embarrassing or complicate political or foreign-policy considerations. President Biden, for example, declined to release a full, unredacted intelligence assessment about the murder of the journalist Jamal Khashoggi, even after a government board recommended it be disclosed to the public. (He released a partly redacted version shortly after entering the White House.)

But Mr. Trump’s approach — and the extent to which his allies extol the virtues of those efforts — is without precedent, according to former intelligence officials and experts on government transparency. “President Trump has been amazing on DECLASSIFICATIONS!” Mr. Pulte, then the acting director of national intelligence, said on social media this summer.

Since returning to office, Mr. Trump has declassified a large volume of files, including about the assassination of former President John F. Kennedy, sightings of U.F.O.s and, under pressure from some of his supporters and members of Congress, millions of pages of documents about the disgraced financier Jeffrey Epstein.

But when it came to the 2020 election or the F.B.I.’s counterintelligence investigation into Mr. Trump’s Russia ties, the Trump administration had engaged in “Olympic-level cherry picking,” said Julia Curlee, a former longtime C.I.A. analyst who left the agency this year and served on the White House National Security Council during the early weeks of the second Trump administration.