House Democrats announced a list of four constitutional law experts who will testify at a Dec. 4 public impeachment hearing, and the panel will include pundits who have criticized the Trump administration and defended the impeachment proceedings. It also includes a witness who has criticized the impeachment investigation.

The Democrats have summoned Noah Feldman, a Harvard Law School professor, to testify in Wednesday’s hearing on the constitutional grounds for impeaching the president. Feldman was among the first people to suggest Trump was trying to bribe Ukrainian government officials into investigating his political rival, former Vice President Joe Biden. Democrats have adopted the term, which Feldman in September said constitutes an impeachable offense.

"What makes Trump’s alleged conduct so terrible is not that he froze aid to Ukraine for a policy purpose. What makes Trump’s alleged conduct outrageous is the appearance that he was doing it for his own personal benefit," Feldman wrote for Bloomberg Opinion.

Feldman has called for a new special counsel to investigate Trump lawyer Rudy Giuliani and Attorney General William Barr, and he also called on Democrats to make the often secretive impeachment proceedings more accessible to the public.

Stanford Law professor Pamela Karlan, a former Obama administration Justice Department official, is also a witness, Democrats announced Monday.

Karlan is among 42 legal scholars who signed a letter before Trump took office urging him to change his views on a number of issues and criticizing his rhetoric.

"Although we sincerely hope that you will take your constitutional oath seriously, so far you have offered little indication that you will," the letter said. "We feel a responsibility to challenge you in the court of public opinion, and we hope that those directly aggrieved by your administration will challenge you in the courts of law."

A third witness, Michael Gerhardt, is a University of North Carolina law school professor who wrote in the Atlantic that the impeachment proceedings are "fully legitimate.”

A fourth witness listed by Democrats, but possibly requested by the GOP, is George Washington University Law School professor Jonathan Turley, who has criticized how Democrats have handled the impeachment process.