The Senate has repeatedly subpoenaed and received new documents, often many of them while adjudicating cases of impeachment.
Moreover, the Senate has heard witness testimony in every one of the 15 Senate trials -- full Senate trials in the history of this republic, including those for presidents Andrew Johnson and Bill Clinton.
Indeed, in President Andrew Johnson's Senate impeachment trial, the House managers were permitted to begin presenting documentary evidence to the Senate on the very first day of the trial.
The House managers initial presentation of documents in President Johnson's case carried on for the first two days of the trial, immediately after which witnesses were called to appear in the Senate.
This has been the standard practice in prior impeachment trials.
Indeed, in most trials, this body has heard from many witnesses, ranging from three in President Clinton's case to 40 in President Johnson's and well over 60 in other impeachments.
As these numbers make clear, the Senate has always heard from key witnesses when trying an impeachment.
The notion that only evidence that was taken before the House should be considered is squarely and unequivocally contrary to Senate precedent.
Nothing in law or history supports it.
To start, consider Leader McConnell's own description of his work at a prior Senate impeachment proceeding.
After serving on the Senate Trial Committee in the case of Judge Claiborne, Leader McConnell described how the Senate Committee quote "labored intensively for more than two months, amassing the necessary evidence and testimony."
In the same essay, Leader McConnell recognized the full body's responsibility for amassing and digesting evidence.
There was certainly a lot of evidence for the Senate to amass and digest in that proceeding, which involved charges against the District Court Judge, the Senate heard testimony from 19 witnesses and it allowed for over 2,000 pages of documents to be entered into the record over the course of that trial.
At no point did the Senate limit evidence to what was before the House, it did the opposite, consistent with unbroken Senate practice in every single impeachment trial, every single one.
For example, of the 40 witnesses who testified during President Johnson's Senate trial, only three provided testimony to the House during its impeachment inquiry, only three.
The remaining 37 witnesses in that presidential impeachment trial testified before the Senate.
Similarly, the Senate's full first impeachment trial, which involved charges against Judge Pickering, involved testimony from 11 witnesses, all of whom were new to the impeachment proceedings and not had -- had not testified before the House.
http://www.cnn.com/TRANSCRIPTS/2001/21/se.09.html