You’re Mitch McConnell, and you’re looking at conducting an impeachment trial in a few months. You’re reasonably confident that there will not be enough votes to remove Trump from office, so your real objective is to limit the damage in the 2020 election. With that in mind, how do you run the trial?
In general terms, he has two choices: he can run it as an actual de novo evidentiary hearing, with lots of live testimony and cross-examination; or he can use the record created by the House and just hear legal argument on it. The first approach, from his perspective, is high risk and high reward; Trump may insist on it in an effort to completely vindicate himself, but if the American public hears lots of credible testimony on TV from clearly honest civil servants about a quid pro quo (which will probably happen), the optics won’t be too good. The second approach is weaker theater, and less risky, but it requires the Senate to rely on a record that won’t be favorable to the GOP cause, to say the least.
There is no perfect choice here. I’m guessing that McConnell will ultimately pick a process that looks more like the second option, and that the defense will ultimately be that the attempts at a quid pro quo were improper, but not egregious enough to constitute “high crimes and misdemeanors.” Will Trump agree to that, as opposed to a long shot attempt at total vindication that is more consistent with his public statements and personality? We’ll see.