Huh. So Trump’s decision to declassify evidence given by ex-spy Christoper Steele about the Trump's alleged links with Russia led to the disappearance of two Russian sources, according to a court document. Via The Guardian:

Christopher Steele, who used to run MI6’s Russia desk, compiled the notorious “Steele dossier” investigating Trump’s connections to Russia. In a witness statement released on Tuesday, Steele said publication of his testimony to the Mueller investigation on the matter, originally classified secret, was an “egregious and reckless act” that “served no purpose other than to expose me and Orbis [Steele’s company], our sources and our methods”.

Trump is attempting to sue Orbis Business Intelligence in England over the dossier, which alleged that he engaged in “perverted sexual behaviour” and paid bribes to Russian officials to further his business interests. The former president is claiming breach of his data protection rights and says the dossier’s claims against him were “false” and “phoney” and caused him reputational damage and distress.

In his witness statement, Steele said the decision to declassify his testimony, taken on Trump’s last day in office, resulted in several Russian sources being exposed and suffering “varying consequences”.

Steele said two of the named Russian sources haven't been seen or heard of since.

"The publication of this document did serious damage to the US government’s Russian operations and their ability to recruit new Russian sources. The claimant’s actions in this regard were truly shocking and arguably constitute one of the most egregious breaches of intelligence rules and protocol by the US government in recent times.”

Sure, Don. Now sue the Senate Intelligence Committee for this.