Those are the rules from the Clinton impeachment. But the Senate has to adopt or write whatever rules it will use in the upcoming trial. The Democrats are advocating that these same rules be adopted for Trump's impeachment. McConnell has not agreed. McConnell can just support a motion to dismiss or adopt rules that allow no additional witnesses to be called - provided he can get 51 votes to do so. Had Pelosi simply sent the Bill of Impeachment to the Senate it is likely that McConnell would have been able to get the 51 votes. Withholding the Bill of Impeachment provides time for pressure to be brought on individual senators to support adoption of fair rules of procedure for the trial.

"It is not necessary to have hope in order to persevere."