If Trump does not fire Mueller and force this investigation to congress his presidency is doomed and the presidency itself will be seriously weakened. Trump is in a very dangerous chess game here and it is time he simply refuses to play. The POTUS is exempt from the law except by congress. He has no duty to investigate himself, or fund a rogue investigation that will intentionally drag on annd do nothing but hound him for four years.
I wish Clinton would have fired Starr, only because the Toon would have certainly been impeached and convicted had he done so. Not so with Trump. The rules have changed and there is no substance whatsoever to the allegations. No one on our side will blame him.