Dems MUST make clear Quid Pro Quo was personal gain only, not for the US gain
If the Democrats don't start making it crystal clear that Trump's quid pro quo request was entirely for personal gain and to fix the election then the GOP strategy of defending it as a normal tool will win.
The GOP has seized upon just about the only thing they can to defend Trump. They're saying "Yes, he did it and it was perfectly legal and normal. We do that all the time." There is truth to that statement in the "We do that all the time" part. We ask for quid pro quo all the time from other nations when it is to benefit the US.
There is a huge risk the GOP is going to spin this as Trump's intention were for the US and not just to get dirt on Biden. Given their mass-marketing machine and FOX propaganda, they have a very decent chance of getting away with this and giving their Senators a cover for voting against conviction.
This is why I think they need to bring more than just the Ukrainian call into the impeachment. They need to bring the clear and obvious obstruction of justice and abuse of office into it. That complicates the messaging, I know.
FFS, though, there has to be a Democratic marketing/branding/messaging firm out there somewhere that can put it in terms people can understand. If we're not hiring them now, we're being damned stupid and we're going to lose again.
Start calling it a Shakedown
or Protection Racket.