U.S. District Court Judge Christopher Cooper turned down a request from Special Counsel John Durham for a ruling that a lawyer facing trial on a false statement charge as part of a wide-ranging “joint venture” involving Hillary Clinton’s presidential campaign, Democrat operatives, and Fusion GPS.

Judge Cooper’s ruling limits evidence and testimony prosecutors can offer against attorney Michael Sussmann at a jury trial scheduled to begin later this month.

Politico reports:

The ruling spares the Clinton campaign and the Democratic National Committee the potential embarrassment of a federal judge finding they were part of a coordinated effort to level since-discredited allegations that candidate Donald Trump or his allies maintained a data link from Trump Tower to Russia’s Alfa Bank. The Clinton campaign disseminated that claim amid a broader effort to call out Trump’s ties to Russia at a time when U.S. intelligence agencies had revealed efforts by the Russian government to interfere in the 2016 election.

Sussmann whose firm at the time, Perkins Coie, represented Hillary’s 2016 campaign and the Democratic National Committee has been charged with lying to the FBI in September 2016, when he approached the bureau’s top lawyer James Baker with what he described as evidence of links between Trump Tower and Russia’s Alfa Bank.

Prosecutors say Sussmann presented his tip to Baker as simply a good-faith attempt to protect national security, when he was actually acting on behalf of the campaign and tech researchers he represented. Cooper said that permitting prosecutors to lay out evidence of such a broad, political conspiracy would amount to a “time-consuming and largely unnecessary mini-trial,” considering Durham has not charged Sussmann with conspiracy but only with a “narrow” false statement to the FBI.

In Sussmann’s case, prosecutors asked Cooper to rule in advance of trial that Sussmann was “acting in concert toward a common goal” with the pro-Clinton operatives, researchers and others. Such a ruling would have given the government attorneys more latitude to introduce emails against Sussmann, but the judge said the scope and membership of the alleged anti-Trump venture was too uncertain to make such a finding.

“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,” wrote Cooper, an appointee of former President Barack Obama. “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.”

He said attempting to link Sussmann to the conspiracy when he isn’t charged with it would “essentially amount to a second trial on a non-crime.”

Sussmann is one of three people charged by Durham since he began his probe. The others are Kevin Clinesmith, who pleaded guilty to doctoring emails used to justify a surveillance warrant against Trump campaign foreign policy adviser Carter Page, and Igor Danchenko, the primary source behind former British intelligence officer Christopher Steele’s anti-Trump “dossier.”