Laid next to the evil activities of other recent presidents, the Trump-Zelensky phone call is a nothing burger. At most, he asked for Zelensky to investigate what appears to be shady dealings by Hunter Biden in Ukraine at the time his father Joe Biden was vice president.
Compare this activity to most recent presidents.
Lyndon Baines Johnson lied about an attack in the Gulf of Tonkin. The Pentagon Papers, the memoirs of Robert McNamara, and NSA publications from 2005, proved material misrepresentation by LBJ to justify an escalation of the war against Vietnam.
The outcome of this false claim, along with another true claim, was the passage by Congress of the Gulf of Tonkin Resolution, which granted Johnson the authority to assist any Southeast Asian country whose government was considered to be jeopardized by "communist aggression". The resolution served as Johnson's legal justification for deploying U.S. conventional forces and the commencement of open warfare against North Vietnam.