Former FBI attorney Kevin Clinesmith's plea agreement could motivate other figures in the Russia investigation to come forward, Wall Street Journal editorial board member William McGurn said Friday.

"I think the big thing that no one’s talking about, if you have a deal ... there’s usually a quid pro quo," McGurn said on "Special Report."

TRUMP SUGGESTS CLINESMITH GUILTY PLEA 'JUST THE BEGINNING OF' DURHAM PROBE FALLOUT

"It probably means that Clinesmith blabbed and all the other parties in this have to be wondering, 'What did Clinesmith tell them about me?' And it may be a signal also for others [that] they might want to cut their own deals."

On Friday, sources told Fox News that Clinesmith would plead guilty to altering a document to claim former Trump campaign adviser Carter Page was "not a source" for another government agency. Page was a CIA informant but that was omitted from a FISA warrant that relied on Clinesmith's false claim.

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The warrant on Page, who had contacts with Russia, has been cited as an example of the FBI abusing its authority in an attempt to surveill the Trump campaign. Prosecutors allege that any relationship between Page and the government would have been important to disclose to the FISA court, to the extent it could help explain interactions Page had had with Russians.

Clinesmith's attorney said his client regretted the change and didn't intend to mislead the court or his colleagues.

The Associated Press contributed to this report.