Attorney Alan Dershowitz on Saturday slammed what he called a judge's "very, very unfair" decision to jail former Trump campaign manager Paul Manafort.

Manafort appeared at the Barrett Prettyman Federal Courthouse in Downtown Washington on Friday where a judge accused him of witness tampering.

Dershowitz said on "Fox & Friends" that there is still a presumption of innocence in Manafort's case.

"Under the law, Manafort is no more guilty of contacting witnesses or attempting to obstruct justice than any of us," he said.

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As reported:

Washington, D.C., Federal District Judge Amy Berman Jackson sent the onetime power player to jail pending trial moments after he pleaded not guilty to the charges, brought against him and his associate, Konstantin Kilimnik of Moscow.

Mueller accused the pair of obstructing justice in the investigation into Russian meddling and potential collusion with Trump campaign associates in 2016.

Manafort's trial before Jackson is expected to take place in September. He is also facing charges brought by Mueller in another federal court, and will appear for that case in August.

The filings last week, signed by Mueller, alleged that Manafort and Kilimnik “knowingly and intentionally attempted to corruptly persuade another person…with intent to influence, delay, and prevent the testimony of any person in an official proceeding.”

Dershowitz said there should have been an evidentiary hearing in which Manafort could present his defense before he was put in jail.

"Why does the government get to win without a hearing or without a trial?" he asked. "I think it's very, very unfair. He's not the only person in jail today for being indicted."

He added that putting someone in jail based solely on what a grand jury says "really is obnoxious to our Constitution."

"There's something very wrong with the system that presumes guilt this way."

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