Some three dozen documents that the Hillary Clinton campaign and others are seeking to keep from special counsel John Durham's team would help prove the case against an ex-Clinton campaign lawyer, Durham's team said in court on May 4.
Inside the paper were allegations that then-candidate Donald Trump's business and a Russian bank had a secret backchannel, claims that the CIA later determined was technically implausible.
Fusion performed opposition research on Trump, including helping compile a dossier filled with unsubstantiated allegations.
Sussman is set to go on trial on May 16 for allegedly lying to the FBI when he said he was not bringing the information on behalf of a client.
Documents attached to some of emails appeared to be draft or final versions of the white paper, he added.
Prosecutors hope to utilize the documents if Seago ends up testifying.
"We have identified Ms. Seago as a core witness that can talk to the relationships between Fusion, between Mr. Joffe, [the Clinton campaign], and Mr. Sussmann," Algor said, describing the emails as "key evidence" regarding relationships between the parties, such as how Fusion and the campaign were "intertwined."
Fusion was paid by the campaign and the Democratic National Committee through Perkins Coie, a law firm that not only employed Sussmann but Marc Elias, who also worked for the campaign.
Durham's team was pushing for U.S. District Judge Christopher Cooper, the Obama appointee overseeing the case, to compel the parties to produce the 38 documents in unredacted form for the judge to review behind closed doors.
Cooper could then determine whether the privilege claims asserted by the campaign, the committee, Perkins, and Fusion were appropriate or unfounded. If the former, they would not be allowed to be used during the trial, at least in unredacted form; if the latter, they could be utilized by Durham's team.
Robert Trout, representing the campaign, argued that the emails could concern opposition research and still be able to be shielded, prompting the judge to bring up how in one email, Fusion's Peter Fritsch told a reporter with Reuters to "do the [expletive] alfa bank secret comms story."
"How is that assisting Mr. Elias in providing legal advice to the campaign?" Cooper wondered.
Cooper later asked Trout if he had any additional documents the campaign would want him to review "that might support its position that Fusion's internal communications on these issues were for the purpose of providing legal support as opposed to pure opposition research and dissemination that is not covered by the privilege."
"I don't," Trout said.
Steven Tyrrell, on behalf of Rodney Joffe, said the emails between his client and Seago were protected by attorney-client privilege because Joffe's lawyer was the same firm that hired Fusion and Sussmann was the one who recommended Joffe meet with Fusion workers.
Algor disputed that notion, noting Sussmann wasn't copied in on the messages and arguing there was no evidence that Seago was being consulted in a way that afforded privilege.
Sean Berkowitz, representing Sussmann, said if the judge allowed the entry of the emails, the special counsel might turn to the approximately 1,500 other documents that were withheld from subpoenas by Fusion on privilege claims.
Algor promised Durham's team would not do so, at least "not for this trial."
Granting the motion to review the documents in private is not "a significant intrusion," Cooper said.
"Whether review of the documents will reveal whether Fusion was creating work product that is covered or not covered remains to be seen. I don't know. So we'll have to see what the emails actually say," he added.