Except that the “whistleblower” can identify the people who illegally leaked the content of the call to him. They might be on the hook for a charge of espionage. He also, with pressure properly applied, might lay out the full conspiracy and involvement of Schiff and company from before the complaint was filed.
I ave always tut tat was the no brained, ask the whistleblower disclose wh shared classified information with him. Prosecute them. And, if he won’t disclose, then yank his clearance and fire him.