Charles Kupperman defies subpoena to testify in impeachment inquiry

Charles Kupperman, former deputy national security adviser, wants a judge to rule on whether he has to testify. The Trump administration claims Kupperman has “constitutional immunity” and therefore doesn’t have to testify. It’s one of the more extreme ways the White House has tried to thwart the growing investigation into the president.

On Friday, a judge ruled that the House’s impeachment inquiry is constitutional. It also ordered the Justice Department to turn over grand jury evidence to Congress.