WASHINGTON (AP) — As U.S. spy agencies ramped up their work to catch foreign meddling in this year's election, a team of CIA experts studied lessons learned from the contentious 2020 vote. Unexpectedly, their report sparked a controversy within parts of the intelligence community.

In a rare move, their study was withdrawn shortly after it was issued in the spring after rank-and-file officers protested that it failed to address the allegations of politics seeping into intelligence that arose in the 2020 election and that remain unresolved for some today.

Reissued in September, the study remains classified and its full contents aren't publicly known. Several people familiar with the matter would say only that it included recommendations on how intelligence leaders could best examine and report election threats attributed to Russia, China and other American adversaries.

The dispute over a relatively routine study and its unusual withdrawal highlight ongoing concerns over how to address the varying foreign threats to U.S. elections — including disinformation, cyber espionage and the amplification of existing divisions within American society. In an increasingly polarized America, some of those tensions have spilled over inside the nominally apolitical world of intelligence, some former officers say.

Some officers have alleged intelligence leaders in 2020 played down findings on Russia to suit the demands of former President Donald Trump, who fired a director of national intelligence in one dispute over Moscow's election meddling. Others say election-related intelligence on China in particular was wrongly played down out of a belief that politicians would misuse it.

The study was requested by the former election threats executive at the Office of the Director of National Intelligence, which oversees the 18 U.S. spy agencies. It was ultimately republished with what's known as a "scope note" explaining the study was focused primarily on senior leaders and not intended to delve into the politicization of intelligence or other potential issues around elections.

Several people described the debate over the study on condition of anonymity to discuss sensitive intelligence matters.

Tim Barrett, the top spokesman for Director of National Intelligence Avril Haines, said intelligence officials have expanded training on objectivity in analysis and worked to better collaborate across agencies.

"We are committed to impartial and inclusive analysis and will continue to provide the insights needed to safeguard our democracy," Barrett said in a statement.

The CIA's Center for the Study of Intelligence produces internal histories of key moments and issues faced across the intelligence community. Its reports are intended to guide current and future officers.

Nicholas Dujmovic, a retired CIA officer who served on the agency's history staff, said any decision to withdraw a study would be unusual, but not unprecedented. Dujmovic, now a professor at the Washington-based Catholic University of America, said he did not have specific knowledge of the recently republished study.

"We're in the intelligence business. We're in the truth business," he said. "Occasionally, if we have information that a study is flawed, we might pull it back and rework it."

One of the study's recommendations was for intelligence agencies to adopt a definition across countries of "election influence" and "election interference."

The lack of a standard practice was flagged by the intelligence community's analytic ombudsman, Barry Zulauf, shortly after the 2020 election. Zulauf wrote in a separate report — an unclassified version of which was released in January 2021 — that analysts studying Russia and China defined "influence" differently, possibly leading to the analysts drawing different conclusions about each country's intentions and actions.

The ombudsman accused Trump's top appointees of delaying and distorting some intelligence findings for political reasons. Some of Trump's attacks on election-related intelligence became public in 2020, including his firing of the director of national intelligence, Joseph Maguire, after his office briefed Congress that Russia was trying to boost Trump's reelection campaign.

Zulauf also found the political pressure may have affected analysts focused on China, who "appeared hesitant to assess Chinese actions as undue influence or interference," in part because they felt Trump would use their findings to attack China and downplay Russia's interventions in support of him.

Ultimately, U.S. intelligence concluded Russian President Vladimir Putin authorized influence operations intended to help Trump while Chinese leaders "considered but did not deploy" measures. In a dissent published in the same report, the national intelligence officer for cyber said he believed China "took at least some steps" in 2020 to try to undermine Trump, primarily through social media and official statements.

This year, U.S. officials are warning of more foreign campaigns to influence midterm races along with the spread of domestic disinformation, the prospect of cyberattacks, and threats and harassment toward election workers.

"The current election threat environment is more complex than it has ever been," said Jen Easterly, the director of the Department of Homeland Security's cybersecurity arm, in a recent media briefing.

Intelligence officials have not given a public briefing on foreign election threats. But unclassified intelligence reports from the Department of Homeland Security, sent to state and local governments, capture some of the current U.S. findings on the intentions of Russia, China and Iran.

Russia is seen as trying to undermine Americans' willingness to support Ukraine eight months into Putin's invasion.

Iran may be interested in "exacerbating social divisions and sowing doubt in U.S. democratic institutions," according to a DHS report issued earlier this year.

And China is probably seeking to influence select midterm races to "hinder candidates perceived to be particularly adversarial to Beijing," according to a DHS report from September. Officials said in the advisory they believe Beijing sees a lower risk in meddling in the midterms versus a presidential election.

Zulauf, the ombudsman, said in his report released last year that the "polarized atmosphere" of the U.S. has "threatened to undermine the foundations of our Republic, penetrating even into the Intelligence Community."

That has made election influence a particularly sensitive topic for spy agencies, former officers say.

"In the golden age, the good old days, people at work didn't know whether your co-workers — also intelligence officers — were Democrats or Republicans," said Dujmovic, the retired CIA historian. "That has changed over time. There is more partisanship in the workforce and that reflects American society in general."