Separation of Powers Restoration Act of 2019 This bill modifies the scope of judicial review of agency actions to authorize courts reviewing agency actions to decide de novo (i.e., without giving deference to the agency's interpretation) all relevant questions of law, including the interpretation of (1) constitutional and statutory provisions, and (2) rules made by agencies. Further, this bill prohibits reviewing courts from deferring to an agency's interpretation of a question of law when the authorizing statutory or regulatory provision is silent or ambiguous with respect to an agency's authority. No law may exempt a civil action from the standard of review required by this bill except by specific reference to such provision.