A federal judge in Virginia on Tuesday rejected a motion from President Trump's former campaign chairman, Paul Manafort, to dismiss the charges against him in Special Counsel Robert Mueller’s Russia probe.

The order means Manafort’s trial next month in Alexandria, Virginia can proceed as scheduled.

The decision Tuesday was a setback for Manafort in his defense against numerous tax and bank fraud charges. Manafort had argued that Mueller had exceeded his authority because the case was unrelated to Russian election interference.

U.S. District Judge T.S. Ellis III issued the ruling. Ellis had previously grilled Mueller's team, questioning whether they brought the case to get Manafort to testify against Trump.

Ellis said those concerns do not “warrant dismissal” of the case. But the judge still expressed skepticism about the reasons the government is prosecuting Manafort.

“Here, we have a prosecution of a campaign official, not a government official, for acts that occurred well before the presidential election,” Ellis wrote in the order.

JUDGE ACCUSES MUELLER'S TEAM OF LYING, TRYING TO TARGET TRUMP

Prosecutors had argued that Mueller was within his authority, citing an August 2017 memo from Deputy Attorney General Rod Rosenstein. The memo shows Rosenstein authorized Mueller to investigate Manafort's Ukrainian work and any related financial crimes.

In May, Ellis harshly rebuked Mueller’s team, suggesting they lied about the scope of the investigation, were seeking “unfettered power” and were more interested in bringing down the president.

"You don't really care about Mr. Manafort,” Ellis told Mueller’s team at the time. “You really care about what information Mr. Manafort can give you to lead you to Mr. Trump and an impeachment, or whatever."

The charges in federal court in Virginia were on top of another round of charges in October. Manafort has pleaded not guilty to both rounds. The charges filed earlier this year include conspiring against the United States, conspiring to launder money, failing to register as an agent of a foreign principal and providing false statements.

Earlier this month, Manafort was jailed after a federal judge revoked his $10 million bail based on new witness tampering charges.

Fox News’ Bill Mears, Jake Gibson, Brooke Singman and The Associated Press contributed to this report.