House impeachment managers inadvertently made the case for the Senate to call former Vice President Joe Biden and his son, Hunter, as witnesses in President Donald Trump’s impeachment trial Thursday — if witnesses are called.

Democrats did so in the course of arguing that President Trump had no legitimate interest in asking the Ukrainian president to investigate the Bidens and Hunter’s involvement with the allegedly corrupt Ukrainian company Burisma.

Rep. Sylvia Garcia (D-TX) bizarrely argued that there was nothing wrong with Biden boasting about forcing Ukraine to remove prosecutor Viktor Shokin from office because Shokin’s investigation into Burisma was “dormant.”

Previously, Democrats had suggested that the investigation had concluded, or that no wrongdoing had been found, but the word “dormant” implies that the investigation, while no active, was still open. That, in turn, confirms that Joe Biden had a conflict of interest when he intervened to fire the prosecutor — and in running Ukraine policy generally.

Then Rep. Garcia claimed, “Biden’s son didn’t do anything wrong in connection with Burisma,” though he earned a fortune for serving on a board with no relevant experience and a recent discharge from the Navy for abusing cocaine.

Rep. Garcia also made assertions that when Biden called for the prosecutor’s removal, he did so because he wanted the prosecutor to be more diligent about investigating Burisma, not less so.

There is only one way to know for sure. Biden and his son have to be called to testify to clarify the facts — if there are any witnesses called at all.

They would provide relevant testimony to prove — or disprove — Democrats’ claim that there was not a “scintilla” of evidence that President Trump’s request for investigations into their activities were in the legitimate interest of the U.S. public.

As Sen. Josh Hawley (R-MO) noted, after he left the Senate chamber during a recess after Rep. Garcia’s argument:

I was very surprised that they chose to make Hunter Biden so central to this presentation, and to insist over, and over, and over again that they knew for a fact about the details, what was going on with Burisma and Biden. And I will just say, that for my part, if we’re going to call witnesses, I think it’s now clear we absolutely must call Hunter Biden, and we probably need to call Joe Biden. Based on the House managers’ presentation today, I think we probably are going to need to hear from the former vice president, if indeed we call witnesses.

Democrats have made the White House’s case for it. As Jay Sekulow, one of the president’s lawyers, remarked later Thursday: “What I don’t understand is for the last five hours it’s been a lot about Joe Biden and Burisma. They kind of opened the door.”

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He earned an A.B. in Social Studies and Environmental Science and Public Policy from Harvard College, and a J.D. from Harvard Law School. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.