Impeachment comes with its own rules - or lack thereof - on standard of proof
(World News Russia)

What is the standard of proof senators will apply to the impeachment trial of President Donald Trump? It depends on whom you ask.  The Constitution provides only bare-bones instructions on the impeachment framework. It does not outline a “standard of proof.� Some legal experts have argued that the seven Democratic House managers  must prove “beyond a reasonable doubt� the president abused his office and obstructed justice, as in a criminal trial. Others contend they must merely present a “preponderance of evidence� to support their impeachment articles, as in many civil cases. The reality is such concerns over the standard of proof seldom...