two good comments re this entire mess:

Bohica
Again, I don’t believe that Little Donnie cared whether Ukraine turned up any real dirt on Joe Biden, just as long as they announced publicly that they were looking into allegations against him. A quick investigation, which would have found nothing substantive, would have done him no good, but an extended one, with unverifiable leaked innuendo galore, was what he wanted.

and

Cedric
Trump obviously thought he got away with the Russia thing and was planning on another repeat in 2020. He got cocky and now it might be his downfall.