Never in the history of our Republic has a President had reason to believe that he would be immune from criminal prosecution if he used the trappings of his office to violate the criminal law. Moving forward, however, all former Presidents will be cloaked in such immunity. If the occupant of that office misuses official power for personal gain, the criminal law that the rest of us must abide will not provide a backstop. With fear for our democracy, I dissent. - Sonia Sotomayor dissenting in Trump v. United States
There is not a syllable in the text of the United States Constitution supporting a presumptive privilege of presidential communications, an absolute immunity barring all civil suits against the President, or any immunity against criminal prosecution after leaving office. In fact, the Impeachment Clause specifically anticipates criminal prosecutions against former Presidents:
Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.
And even more problematically, if that is possible, the Constitution specifically provides a limited immunity for members of Congress in certain circumstances, so we know that the Framers understood how to give government officials immunity when they wanted to do so. For the Court to create a common law immunity for the President for his criminal acts with serious limits on how the prosecution can prove the President committed unofficial acts is penumbras and emanations on steroids.
Conservative legal academics, judges, and politicians for decades accused the Warren and Burger Courts of not taking text seriously and engaging in result-oriented jurisprudence. Griswold and Roe were exhibits 1 and 2 in that on-going commentary. But it turns out, as it almost always does within constitutional law, that the strong objections to the reasoning and processes of Griswold and Roe had nothing to do with process and reasoning and everything to do with politics and ideology. Conservatives have now taken penumbras and emanations to a new level of aggressive judicial review across a broad spectrum of constitutional litigation.