Hearsay, speculation, assumption based on rumour-mongering assumption?

We're all aware of what this expert informed analysis lead to at the last election! If Trump has no case to answer? Why then is he doing everything in his power to prevent witnesses giving evidence to congress?

To the point of some ignoring legal subpoenas?

What's he afraid may also be revealed!?

I mean, he must know a standing President cannot be prosecuted!?
Alan B.