IMHO, President Trump should ignore the democrats’ show trial entirely. The only purpose of the show trial is to placate the democrats’ far left wing.
If he does not ignore it, then he should file suit in a carefully selected conservative judicial district and seek a nationwide injunction on the grounds that a Senate show trial of a former President is unconstitutional.
It’s going to be fun when Trump lawyers show clips of Maxine, Pelosi, Squad inciting violence against Trump supporters.