Subjective motivations should be irrelevant

A law professor attacks this Bill Barr opinion:

The Supreme Court has traditionally refused, across a wide variety of contexts, to inquire into the subjective motivation behind governmental action. To take the classic example, if a police officer has probable cause to initiate a traffic stop, his subjective motivations are irrelevant. And just last term, the Supreme Court appropriately shut the door to claims that otherwise-lawful redistricting can violate the Constitution if the legislators who drew the lines were actually motivated by political partisanship.

What is true of police officers and gerrymanderers is equally true of the President and senior Executive officials. With very few exceptions, neither the Constitution, nor the Administrative Procedure Act or any other relevant statute, calls for judicial review of executive motive. They apply only to executive action. Attempts by courts to act like amateur psychiatrists attempting to discern an Executive official's "real motive" — often after ordering invasive discovery into the Executive Branch's privileged decision-making process — have no more foundation in the law than a subpoena to a court to try to determine a judge's real motive for issuing its decision. And courts' indulgence of such claims, even if they are ultimately rejected, represents a serious intrusion on the President's constitutional prerogatives.