Question...can the VP cast a tie breaking vote in that case, or is that out in a senate trial?
Well the VP can only vote in the case of a tie, he does not preside over the Senate during impeachment proceedings. But the Constitution does not say that he must be presiding in order to exercise that privilege. As the Constitution does not specifically prohibit it, I would argue the VP can in fact vote. But I’m sure Roberts would disagree with me.
In summary: it’s unclear.
In the early years of our republic, the VP and President were elected separately, they could even be from different political parties.
I read that for this impeachment thing, the tie would be broken by Judge Roberts.
I heard Ted Cruz talking several days ago that he thought it would be better to have the trial and find Trump innocent of the charges than to just dismiss it out right, as that still leaves the idea of “impeachment” out there for the democrats to harp on.