From a legal point of view, they don't.
I've said more than once that I don't think any of this is legally valid. But what it is is very good cover for the Republicans to protect Trump under the guise of being the party that's
actually trying to seen justice done in protecting a president who has done nothing wrong against the witch-hunt that's being held against him.
If that's his actual argument then he is engaging in mind reading, and/or parroting Republican talking points.
I'll let you guess which is more likely. Although it should be noted that the actual part of my post you quoted and said this about was explicitly laying out Republican talking points, rather than what Turley said. Turly
did say that the case was weak, but that wasn't the information I was conveying in the particular part of my post that you here quoted.
I don't think Democrats have been out-maneuvered. I think it was a case where they were dealt a losing hand to start with (excessively corrupt GOP, unfavorable senate elections schedule, underlying base of racist Trump supporters) and are simply making the best of a bad situation. You can do everything correct and still come out with the short end of the stick.
I don't think they
have done everything right, because they didn't make the counter-arguments they could make, and they didn't cross-examine him. I think they fed in to the Republican narrative.
I felt yesterday was in stark contrast to, for example, the Mueller testimony, where the Republicans looked like they were desperately flailing while the Democrats were mostly trying to get at the truth. Instead here the Republicans had a witness who came over very well, who had obviously done a lot of homework, and who made arguments that had enough of a veneer of credibility that they can be leaned on in a way that can be persuasive to the public at large.
Trump supporters were never going to turn on Trump (even if he gave a signed confession) because he gives them the bigotry they crave. GOP senators were never going to turn on Trump because they fear his base, and are corrupt themselves. And Trump's defenders will always accept bogus arguments that support Trump, regardless of how silly those arguments are, because they like them some racism.
I'm not talking about swaying Trump supporters. I'm talking about the unaffiliated, the independent, the people in the middle. Trump supporters are a minority, and even with voter suppression, gerrymandering, foreign help, etc. they can't win with just the hardcore base alone. They need the people in the middle. If they turn to be against Trump - if supporting Trump looks like it will actually harm the careers of Republicans and harm the electability of the Republican party/Republican politicians, then the Republicans will turn on Trump.
Instead the Democrats have allowed there to be a situation where a reasonable floating voter who is loyal to neither party and who hasn't closely followed what is going on can legitimately and honestly think that the case against Trump is unfair and weak - illegal or a threat to American democracy, even. I'm not entirely sure that was avoidable, but I
am sure that there was more that could have been done to prevent it.