The Democratic chair of the House Judiciary Committee on Tuesday issued a direct challenge to President Donald Trump: put up or shut up.

In a letter (pdf) addressed to Trump, Rep. Jerry Nadler (D-N.Y.) told the president that he and his legal team are welcome to participate in public impeachment hearings in the Judiciary Committee—which will begin on Wednesday, December 4. Nadler informed Trump that the preident has until 6pm Sunday December 1 to decide whether or not to take part in the hearings.

“The President has a choice to make,” Nadler said in a statement, “he can take this opportunity to be represented in the impeachment hearings, or he can stop complaining about the process.”