[Verginius Rufus]

They probably expect to win in a landslide in 2020 (no one they know likes Trump) and it's just a question of figuring out who would make the strongest ticket, after pretending to leave it to the voters in the primaries to decide. So best not to alienate low information voters with an impeachment circus which will leave Trump still in office.

Biden/Abrams?
Bernie/Kamala?
Kamala/Buttigieg?
Biden/Castro?
Abrams/Waters?
Buttigieg/Booker?

[lasereye]

They probably expect to win in a landslide in 2020

You would think they wouldn't be interested in impeachment if they really believe that.

[Eleutheria5]

“Buttigieg/Booker?”

Or Booker/Buttigieg?

Which one would be the catcher, and which one the pitcher?