Last week, the impeachment trial continued, with Wednesday and Thursday devoted to senators submitting questions to Chief Justice John G. Roberts Jr., who read them and seldom provided any other input.We learned of new theories of impeachment and the week concluded with a vote on witnesses. In last Monday’s column, I referred to Roberts as the “Great Presider.” I address some of the issues from last week.The Senate shall have the sole power to try all impeachmentsThe Constitution provides the above …