Schiff's approach in talking about the founders is useful I think, in appealing to people like Lamar Alexander. It won't change their votes, of course. But one possible outcome is at the end of this process several Senate Republicans say something like, "There is pretty clear evidence Trump did something improper. We strongly urge him not to collude with a foreign government in the upcoming election. That said, we're not sure that this conduct is impeachment-worthy, particularly less than a year before the election."
The outcome of this trial -- in terms of whether Trump will be removed from office -- is already determined. But what message comes from this trial ("Trump did nothing wrong," or "Trump did a lot wrong') is not decided. I'm sure Ted Cruz or Tom Cotton will say Trump's call was perfect. But I will be curious what Alexander, Romney and others say at the end.