[Uncle Sham]

"barring new evidence, may be fair, reasonable or defensible but it isn't Constitutional."

You are missing the point. The Senate can make it's own rules as to how it "judges" the content of that which the House presents in their article of impeachment. The Senate is constitutionally barred from helping the house put forth it's case or assist the House in the discovery phase. "New" evidence or testimony falls under the discovery phase of an impeachment, NOT the judging phase. The Senate judges whatever the House discovers and argues.

[semimojo]

The Senate is constitutionally barred from helping the house put forth it's case or assist the House in the discovery phase.

You keep saying that but haven't pointed to the part of the Constitution that backs up your assertion.