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The trial of former Clinton campaign lawyer Michael Sussmann began May 16, as Special Counsel John Durham’s years-long investigation into the origins of the Trump-Russia probe finally landed in court. 

Here is what you need to know.

Sussmann is charged with making a false statement and has pleaded not guilty.

The trial is being held in the U.S. District Court for the District of Columbia with Judge Christopher Cooper presiding.

DURHAM RELEASES FORMER CLINTON LAWYER MICHAEL SUSSMANN'S TEXT MESSAGE, SAYS HE PUT 'LIE IN WRITING'

Durham alleges Sussmann told FBI General Counsel James Baker in September 2016 — less than two months before the 2016 presidential election — that he was not doing work "for any client" when Sussman requested and attended a meeting where he presented "purported data and ‘white papers’ that allegedly demonstrated a covert communications channel" between the Trump Organization and Alfa Bank, which has ties to the Kremlin.

John Durham Michael Sussmann

John Durham and Michael Sussmann (Sussman photo from Perkins Coie)

Durham alleges Sussmann lied in the meeting, "falsely stating to the general counsel that he was not providing the allegations to the FBI on behalf of any client."

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Durham, in a filing in the weeks leading up to the trial, said "the night before the defendant met with the general counsel, the defendant conveyed the same lie in writing and sent the following text message to the general counsel’s personal cellphone."

"Jim — it’s Michael Sussmann. I have something time-sensitive (and sensitive) I need to discuss," the text message stated, according to Durham. "Do you have availability for a short meeting tomorrow? I’m coming on my own — not on behalf of a client or company — want to help the Bureau. Thanks."

Baker replied: "OK. I will find a time. What might work for you?"

Durham in February first revealed that the government would attempt to establish at trial that among the data "exploited" was domain name system (DNS) internet traffic relating to "a particular healthcare provider, Trump Tower, Donald Trump's Central Park West apartment building and the Executive Office of the President of the United States (EOP)."

Hillary Clinton

In this July 8, 2016, file photo, Democratic presidential candidate Hillary Clinton speaks at the African Methodist Episcopal Church national convention in Philadelphia.  (AP Photo/Matt Rourke, File)

In February, Durham said data was exploited "by mining the EOP's DNS traffic and other data for the purpose of gathering derogatory information about Donald Trump," adding the data was used to establish "an inference" and "narrative" tying Trump to Russia.

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Durham also alleges that Sussmann in February 2017 provided an "updated set of allegations," including the Alfa Bank claims, and additional allegations related to Trump to a second U.S. government agency, which Fox News has confirmed was the CIA.

The federal judge presiding over the case, Cooper, has said the prosecution can present evidence and question witnesses about the DNS data but has limited the evidence Durham and the prosecution can present against Sussmann during trial.

The prosecution has argued that Sussmann desired to conceal a "joint venture" with the Clinton campaign, which Cooper wrote that the prosecution claims "supplied a motive" for Sussmann to "misrepresent" to Baker "that he was not providing the data to the FBI on behalf of any client, when he was actually representing both Mr. Joffe and the campaign." 

That was a reference to tech executive Rodney Joffe, who has not been named in Durham’s filings and has not been charged with a crime.

Trump Trump Tower

President-elect Trump speaks to reporters at Trump Tower in New York Dec. 6, 2016. (AP Photo/Andrew Harnik)

Sussmann’s defense has denied he had an attorney-client relationship with the Clinton campaign that covered activities related to the Alfa Bank data.

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"The court will exercise its discretion not to engage in the kind of extensive evidentiary analysis that would be required to find that such a joint venture existed and who may have joined it," Cooper wrote in a filing this month. "While the special counsel has proffered some evidence of a collective effort to disseminate the purported link between Trump and Alfa Bank to the press and others, the contours of this venture and its participants are not entirely obvious.

"Because no conspiracy is charged in the indictment, this undertaking would essentially amount to a second trial on a non-crime conducted largely for the purpose of admitting ‘other acts’ evidence of Mr. Sussmann’s motive rather than his commission of the singular and narrow crime with which he has been charged."

Sussmann’s trial is expected to last two weeks.

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The trial is the first to emerge out of Durham’s investigation into the origins of the Trump-Russia probe.

William Barr

Attorney General William Barr speaks during a news conference Dec. 21, 2020, at the Justice Department in Washington. (Michael Reynolds/Pool via AP)

Durham was tapped in 2019 by Attorney General Bill Barr to investigate the origins of the FBI’s original investigation into the Trump campaign, which led to the appointment of Robert Mueller as special counsel.

At the time, Durham was serving as U.S. attorney for Connecticut.

Special Counsel Robert Mueller

Special Counsel Robert Mueller speaks at the Department of Justice in Washington about the Russia investigation May 29, 2019.  (AP Photo/Carolyn Kaster, File)

Mueller's investigation yielded no evidence of criminal conspiracy or coordination between the Trump campaign and Russian officials during the 2016 presidential election.

In October 2020, Barr appointed Durham as special counsel to ensure he would be able to continue his investigative work — regardless of the outcome of the 2020 presidential election.

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Durham has indicted three people as part of his investigation: Sussmann in September 2021, Igor Danchenko in November 2021 and Kevin Clinesmith in August 2020.

Danchenko was charged with making a false statement and is accused of lying to the FBI about the source of information he provided to ex-British intelligence officer Christopher Steele for the anti-Trump dossier.

Christopher Steele wrote dossier on Trump

Christopher Steele, a former British spy who wrote a 2016 dossier about alleged links between Donald Trump and Vladimir Putin. (Aaron Chown/PA Images via Getty Images)

The unverified dossier, which contained allegations of purported coordination between Trump and the Russian government, was authored by Steele, an ex-British intelligence officer, and commissioned by opposition research firm Fusion GPS.

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Perkins Coie is the law firm through which the Democratic National Committee (DNC) and the Clinton campaign funded the anti-Trump dossier.

Clinesmith was also charged with making a false statement. Clinesmith had been referred for potential prosecution by the Justice Department's inspector general's office, which conducted its own review of the Russia investigation.

Specifically, the inspector general accused Clinesmith, though not by name, of altering an email about Trump campaign aide Carter Page to say that he was "not a source" for another government agency. Page has said he was a source for the CIA. The DOJ relied on that assertion as it submitted a third and final renewal application in 2017 to eavesdrop on Page under the Foreign Intelligence Surveillance Act (FISA).

U.S. Attorney John Durham

U.S. Attorney John Durham outside federal court in New Haven, Conn., after the sentencing of former Gov. John Rowland. (Bob MacDonnell/Hartford Courant/Tribune News Service via Getty Images)

In a special counsel scope order, Barr wrote that Durham "is authorized to investigate whether any federal official, employee or any other person or entity violated the law in connection with the intelligence, counter-intelligence or law-enforcement activities directed at the 2016 presidential campaigns, individuals associated with those campaigns, and individuals associated with the administration of President Donald J. Trump, including but not limited to Crossfire Hurricane and the investigation of Special Counsel Robert S. Mueller, III."

Under U.S. code, the special counsel would produce a "confidential report" and is ordered to "submit to the Attorney General a final report, and such interim reports as he deems appropriate in a form that will permit public dissemination."