“Modern separation-of-powers jurisprudence—including key decisions decided during the Supreme Court’s 2023-24 term—has been critiqued on the grounds that it constitutes “judicial aggrandizement,” i.e., that it impermissibly empowers federal courts to decide separation-of-powers questions better left to Congress and the President. This “judicial aggrandizement” critique goes too far to the extent it suggests that federal courts may not play any role in enforcing the separation of powers. After all, ours is a system of a President and Congress constrained by a written Constitution—not a King in Parliament free to act outside of judicial constraint…”