Yup, this immunity decision and their ruling overturning Chevron deference will fundamentally change how our government functions. If expert agencies are no longer able to rely on their expertise and presidents are officially above the law, then our democracy is over. Whoever holds the office of the presidency is now a de facto king (in the words of Justice Sotomayor). The comparison to the Enabling Act is super useful for people who care at all about history or democracy.
In light of the SCOTUS opinion that "official acts" by a president are immune from criminal prosecution, and the Trump defense stating that "they could see" an assassination order by a president against a political opponent that has been "identified" as corrupt ...