During oral argument in the Trump immunity case, Justice Kavanaugh articulated a strong understanding of the "clear statement" rule. Under this principle, statutes should be read to not apply to the President unless there is a clear statement that Congress intended to subject the President to that constraint. Kavanaugh suggested there is always a "serious constitutional question whether a statute can be applied to the president's official acts." I wrote about some of Kavanaugh's questions in this post.
Professor Mike Ramsey observed that the clear statement rule, or the "presidential nonapplicability canon (if we can call it that) parallel a view of the major questions doctrine as a substantive canon." I agree with Ramsey. Both the clear statement rule, and the major question doctrine, are substantive canons to avoid potential violations of the separation of powers. Justice Gorsuch explained in West Virginia v. EPA that the major question doctrine is best viewed as an avoidance canon in service of the non-delegation doctrine. That is, the Court will require a clear statement that Congress intended to empower an agency to resolve a "major question" in order to avoid deciding if such a broad delegation would even be constitutional. Likewise, with the Presidential Avoidance Canon, as I described it during the Trump years, the Court will require a clear statement that Congress intended to limit the President's power in order to avoid deciding if such a limitation on the President's power would violate Article II.
The clear statement rule and the major question doctrine both function as substantive separation of powers canons in order to avoid deciding if federal actions are unconstitutional.
