WASHINGTON — A judge on Friday ordered the Justice Department to give the House secret grand jury testimony from special counsel Robert Mueller’s Russia investigation, handing a victory to Democrats who want it for the impeachment inquiry against President Donald Trump.

Chief U.S. District Judge Beryl Howell ordered the department to turn over the materials by October 30. A Justice Department spokeswoman said it was reviewing the decision.

The material covered by Howell’s order includes redacted grand jury material mentioned in Mueller’s report, which is the only piece of the document that Democrats have yet to see.

In a 75-page ruling accompanying the order, Howell slashed through many of the administration’s arguments for withholding materials from Congress. While the Justice Department said it couldn’t provide grand jury material under existing law, “DOJ is wrong,” she wrote. And while the White House and its Republican allies argued impeachment is illegitimate without a formal vote, she later added, “A House resolution has never, in fact, been required.”

The judge also rejected the Justice Department’s argument that impeachment isn’t a “judicial proceeding” under the law, for which the information could be disclosed.

Justice Department lawyers argued against providing the materials at a hearing earlier this month. They said House Democrats already had sufficient evidence from Mueller’s investigation, including copies of summaries of FBI witness interviews.

Many of the key witnesses in the Trump orbit, including former White House counsel Don McGahn, submitted to voluntary interviews before Mueller’s team rather than appear before the grand jury, making it unclear how much significant new information tied to the president is contained in the grand jury transcripts.

The department had also argued that the House panel couldn’t show how the material would help in the committee’s investigations of Trump.