Adverse Inference is why we can say that trump is guilty and should be removed from office. There is no excuse for the obstruction by trump.
The adverse inference is based upon the presumption that the party who controls the evidence would have produced it, if it had been supportive. Adverse inference can also apply to a witness known to exist but the party refuses to identify or produce.
Adverse inference - Wikipedia
According to Lawvibe, "the 'adverse inference' can be quite damning at trial. Essentially, when plaintiffs try to present evidence on a point essential to their case and can't because the document has been destroyed (by the defendant), the jury can infer that the evidence would have been adverse to (the defendant), and adopt the plaintiff’s reasonable interpretation of what the document would have said...."
Adverse inference - Wikipedia
An adverse inference generally is a legal inference, adverse to the concerned party, made from a party's silence or the absence of requested evidence. For example, as a sanction for spoliation of evidence, a court may instruct the jury it could draw an inference that the evidence contained in the destroyed documents would have been unfavorable.
Adverse Inference Law and Legal Definition | USLegal, Inc.
The courts decide that someone like the Pres is required to testify or turn over evidence. It's not the whims of political enemies in Congress who decide this, and until then the separation of powers exists for this very reason.
Members of the Senate have these same protections from the Executive branch as well. Right now all we are seeing is the shell game by the leftist Democrats, moving around the goal posts of impeachment..... looking for any reason to remove him, since day one, always changing their story, always finding someone and something new, that is never quite verified but always gets a big news story to sway public opinion.
This is all about the election. The Dems know they cant impeach him but they will keep it up right to the election to satisfy their base. It would be political death for anyone of them to back down now.