Don't expect FBI Director James Comey to reveal much about the bureau's months-long investigation of potential coordination between the Trump campaign and Russia when he speaks publicly before members of Congress on Wednesday.
In fact, there's no guarantee Comey and his agency will ever fully lay bare those findings for the American public, because such investigations rarely end in criminal charges that offer a full picture.
Some measure of information will certainly come to light through multiple congressional investigations. And political pressure will fall on Comey and the Justice Department to make public what investigators have learned.
The most obvious vehicle for disclosing details of a government investigation is through a criminal indictment, but counterintelligence investigations such as the one into President Donald Trump's campaign and its possible ties with Russia rarely end with charges. These cases involve extremely sensitive sources and methods that officials are loath to drop clues about. American officials often conclude that spy-related activity they uncover isn't actually criminal in nature, or can be addressed through a tool other than prosecution.
"The vast majority of counterintelligence investigations will never see the inside of a courtroom," said former FBI counterintelligence agent Asha Rangappa, an associate dean of Yale Law School. "The purpose of a counterintelligence investigation isn't to find people, build a criminal case and put them in jail."
The purpose, instead, is to root out spies.
It's impossible to say when or how the investigation will end. But if the work concludes without criminal charges, a Justice Department inclined to keep intelligence matters secret will invariably confront demands to reveal its findings given the extraordinary public interest in the investigation. New Deputy Attorney General Rod Rosenstein has declined to commit to such a disclosure, and hovering in the background is Comey's decision to make detailed public statements after the FBI declined to recommend charges in its investigation of Hillary Clinton's use of a private email server.
"I am assuming that at the end of the inquiry that there will be an effort to apprise the public of what they've learned," said Clinton campaign spokesman Brian Fallon. "Even if it never produces any criminal charges, there is a deep public interest in getting to the bottom of exactly what was the nature of the Russian intrusion into our election."
Trump weighed in on the Russia probe late Tuesday on Twitter.
"FBI Director Comey was the best thing that ever happened to Hillary Clinton in that he gave her a free pass for many bad deeds! The phony Trump/Russia story was an excuse used by the Democrats as justification for losing the election. Perhaps Trump just ran a great campaign?" Trump said in a couple of tweets.
The FBI's counterintelligence probe that began in late July is investigating possible coordination between Russia and Trump associates to sway the presidential election in Trump's favor. U.S. intelligence officials have blamed Russian intelligence services for interfering in the election through hacking Democratic email accounts.
Besides the FBI, House and Senate committees investigating Russian interference in the presidential election and ties between Trump aides and the Kremlin have been holding public hearings and could ultimately publicize their findings - though it's unclear how extensive those reports would be. Last week, congressional officials said Michael Flynn, Trump's first national security adviser, appeared to violate federal law when he failed to seek permission or inform the U.S. government about accepting tens of thousands of dollars from Russian organizations after a trip there in 2015. The Pentagon's inspector general is investigating those payments.
Comey on Wednesday is testifying publicly before the Senate Judiciary Committee, a regular occurrence as the panel oversees the FBI. On Thursday, he is to speak behind closed doors to the House committee looking into the Russia issues.
There are limited examples of counterintelligence investigations resulting in criminal charges, including the 2010 arrests of 10 deep cover Russian spies who were expelled from the U.S. and swapped for Russians imprisoned for spying for the West. In 2015, the Justice Department prosecuted Evgeny Buryakov, a Russian intelligence agent who posed as a New York banker.
But prosecution isn't the primary goal of a counterintelligence investigation. Officials looking to better comprehend another nation's spy efforts may not want to publicly reveal anything that could encourage a country to switch its tactics, or may see diplomacy as a preferable option.
"Our constitution allows people who are accused of a crime to know the evidence against them," Rangappa said. "That not only exposes everything we know, it can also expose our methods and sources."
Added Christopher Lynch, a former CIA and FBI counterintelligence analyst: "You've got to make a judgment: Is that source going to continually be there and provide more and more information in the future, or are you putting the source in jeopardy by identifying publicly in a criminal charge that that's a source?"
Since the Justice Department traditionally does not confirm the existence of an investigation, it's ordinarily equally reluctant to announce when one concludes without charges.
But there have been exceptions, particularly in high-profile matters involving elected officials.
Federal prosecutors in New York and Washington issued statements when they closed without charges investigations into those cities' mayors, and the Justice Department in 2015 provided to Congress a detailed explanation of its decision not to pursue an Internal Revenue Service prosecution over the processing of applications for tax-exempt status.
The most striking departure was the July news conference in which Comey detailed the bureau's decision to not recommend criminal charges against Clinton. The American people, he said then, ``deserve those details in a case of intense public interest.''
Though the announcement removed the threat of criminal prosecution, Democrats nonetheless criticized Comey for calling Clinton and her aides "extremely careless" in their handling of classified material, a characterization they said strayed from the FBI's just-the-facts protocol.
Against the backdrop of that decision, and in recognition of the extraordinary public interest in the Russia investigation, there will almost certainly be a mechanism for providing to the public details of the government's findings - even if a full, and more extensive, report remains classified, Fallon said.
Comey has said he wants to be "transparent" when it comes to discussing foreign meddling in American politics, though it's not clear what shape that will take.
"He won't want it to seem like he's pulling punches with respect to President Trump," Fallon said.