If the Democrats need more witnesses, theyre admitting their case is a loser.
No wonder they sat on their turd impeachment for a month after voting for it.
I think the Republican response should be that the Democrat call for witnesses is proof that the impeachment was passed on fraudulent grounds and should be dismissed.
Since the entire body of the House didn't authorize subpoena power for witnesses, the obstruction of Congress charge is invalid. Calling witnesses now is ex post facto.
The remedy for an invalid basis for witnesses in the House is not to allow witnesses in the Senate, it's to throw out the charge from the House for lack of proper predicate, and make them do it again, properly.
-PJ
It means they didn't do their homework. It is the duty of the attorney seeking to introduce witnesses to explain what the testimony will consist of and why it is relevant to the factual issues before the court.