Washington (CNN) Rep. Doug Collins, the top Republican on the House Judiciary Committee, is telling a federal judge that the Democrats' impeachment investigation has no legal basis.

In a proposed amicus brief filed Thursday with a federal judge in Washington, Collins says the court should reject a request by the Democratic-led Judiciary Committee to see information from the secret grand jury used in former special counsel Robert Mueller's investigation.

Collins reiterates the GOP's argument that the full House must vote to authorize an impeachment inquiry, and it has not done so.

"If the Committee seeks judicial interference in its proceedings, the House must take the procedural and political action required of it by holding a vote to delegate its impeachment power to the Committee," Collins wrote. "Barring such action, the Committee advances an unprecedented and untested audience."

House Speaker Nancy Pelosi announced last month that several Democratic-led committees would conduct impeachment-related investigations. That declaration, Collins says, does not pass muster as a legal basis.

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