What are the Constitutional limits of Presidential Immunity?

It all hinges on the semantics (in context) of the word "nevertheless" in Article I, section 3, clause 7

If a President's actions could plausibly be seen as either "official acts" or alternatively could plausibly be seen as "acts for personal gain," as a matter of law the courts should always deem them to be "official acts”: Reasonable uncertainties and/or ambiguities should ALWAYS be resolved in favor of a criminal defendant. Here’s why:

Per the rule of lenity, criminal law should always be interpreted in whatever way would be the most favorable for a criminal defendant, provided that such an interpretation is syntactically and semantically plausible (Constitutionally required, per SCOTUS.) And given the fact that the burden of proof is Constitutionally on the prosecution, and not on the accused, an analogous principle also applies to the interpretation of the facts of a case.

An act of an “official” is not an “official act” simply because an official performs it. Nor is an act of an official illegal just because it’s not an “official” one. Nor is an official’s act necessarily legal simply because it’s facially “official,” such as an act that is specifically authorized or mandated by a law that specifies the duties and/or responsibilities of an official.

An illegal action cannot semantically qualify as an "official act," by definition of "official" and "illegal.” That fact reveals a troublesome gray area where one law (e.g., the US Constitution, or a Federal statute) explicitly, or even by implication, allows (or even requires) an official to take action, but a different law criminalizes that same facially “official act” because of the way that the action was performed, and/or because of when it was performed, and/or because of whom the action affected, and/or because of how people were affected by the action.

Consider this analogy: Most Acts of Congress are not explicitly authorized by the Constitution, but instead are implicitly authorized by the “Necessary and Proper” clause. That clause acts to restrict the scope of the powers granted to Congress in Article I, section 8 by the additional constraint that such actions must not only be authorized by Article I, section 8, but must also be both “necessary” and “proper.”

The term “proper,” as used in the context of a Constitution and in the late 18th century, is synonymous with “rightful, not ethically invalid.” In other words, thanks to the “Necessary and Proper” clause, the power granted to “build post roads” is not a grant of authority to kill innocent people, or take their property without just compensation, in order to build post roads.

To use an example raised by Justice Sotomayor: The Constitution grants the President the authority and the responsibility to defend the United States from all enemies, foreign and domestic. Conversely, the US Code criminalizes murder. So then, what is the Constitutionally-correct view of a drone strike ordered by a President that results in the death of a US citizen who has not been convicted (or perhaps not even accused by indictment) of any crime whatsoever?

Let's be clear: There is no valid ethical principle that justifies killing an innocent person, not even in a war situation. Unfortunately, the US Constitution makes its own rules, regardless of the underlying ethics. That does not always lead to an ethically-correct result.

Mark Smith (the presenter in the video linked below, and a Constitutional lawyer licensed to practice in front of the Supreme Court) argues that the right way to judge such issues is to distinguish between acts that are ethically incorrect ("malum in se," as the legal profession labels it) and those that violate arbitrary procedural rules ("malum prohibitum,") regardless of whether those rules are codified as statutes (criminal laws) or as regulations (where only civil penalties would be imposed.)

But there's another Constitutional issue that takes precedence: Can a President whose facially “official” action(s) while in office were nevertheless illegal be criminally prosecuted under Federal law for his or her illegal actions? And if so, under what circumstances?

Note first that a sitting President may Constitutionally pardon him or herself, and that any such pardon(s) would not be judicially reviewable, thanks to the separation of powers doctrine: The power to pardon is granted directly by the Constitution to the President, without any limitation. So a President could give himself immunity for whatever he chooses to do (or has already done) while still in office. If SCOTUS rules that Presidents don’t have immunity, or that there are limits to that immunity, the predictable result will be that Presidents would issue blanket pardons for themselves before leaving office.

Secondly, note that the President is the highest Constitutional authority in the Executive Branch. That means that ALL employees of the Federal government that work for ANY Federal Department or Agency are under the authority of the President. That includes the Department of Justice, and all US Attorneys. See "The Saturday Night Massacre" for how that effects the ability of a US Attorney to prosecute a sitting President.

Thirdly, note that the Constitution explicitly makes the primary responsibility of the US President "the faithful execution of the laws." So ANY action of a sitting President that is arguably for the purpose of enforcing Federal law automatically qualifies facially as an "official act," unless the action taken for that purpose is itself illegal.

Bottom line: A President cannot legally act to "enforce the law" by breaking one or more other laws in the process, whether or not the action facially qualifies as “official,” for the same reason that Congress cannot authorize the building of “post roads” in such a way that it would predictably result in the taking of private property without just compensation.

The same principle applies to acts that are generally allowed by law in general—such as giving a speech—but are nevertheless illegal in a specific instance. See Brandenburg v. Ohio for the current binding SCOTUS precedent that lays out how to determine when and why a speech might, or might not, be illegal, specific to the sort of charges for which a former President has been indicted.

And finally, here are the words of the Constitution that directly apply to the prosecution of a President:

"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." ~ Article I, section 3, clause 7

The key word in that clause is "nevertheless." That conjunctive adverb means "despite what was just mentioned." So, despite the fact that an office holder has been removed from office due to having been convicted by the Senate for whatever misdeed the House had accused the person of, the Constitution asserts that any such person does not therefore have immunity from subsequent prosecution just because they had been tried and convicted by the Senate.

Question: Why did the Constitutional Convention deem it necessary to make that assertion regarding the absence of any immunity from prosecution subsequent to a conviction by the Senate?

The reason that that question is pivotal in understanding Presidential immunity is because of the principle of interpretation first canonized by the US Supreme Court in the most important, landmark ruling it has ever made: Marbury v. Madison—the case where the Supreme Court deemed that the Constitution had granted it the power of "Judicial Review"—the power to void laws, regulations and other official actions of either Congress, or of the Executive Branch, as Unconstitutional.

One of the precedent-setting holdings of Marbury vs. Madison was the following:

It cannot be presumed that any clause in the Constitution is intended to be without effect, and therefore such construction is inadmissible unless the words require it. ~ Marbury v. Madison, 5 U.S. 137

That each clause of the Constitution must be consequential, and not superfluous, is one of the foundational principles of exegesis that the Supreme Court uses in interpreting the Constitution. One consequence of this principle is that the Supreme Court will not interpret a later Amendment in such a way so as to render any clauses present before that Amendment was added impotent or irrelevant, unless it is abundantly clear that such was the intent of the later Amendment—perhaps because the later Amendment explicitly states that an earlier clause is repealed, or perhaps because the later Amendment contradicts an earlier clause, and the conflict can only be resolved by assuming the implied intent was to repeal or nullify the other clause.

Note that it is logically impossible for a clause to have substantive, material and consequential effect unless each clause also has unique effect: If the effect of a clause were not unique, then it could be removed without substantive effect or consequence.

Therefore, the fact that a clause has been asserted in the Constitution MUST CHANGE what the Constitution requires, or allows, or forbids. Given that, we must ask this: “How does the addition of the final dependent clause of Article I, section 3 change what the Constitution allows, or requires, or forbids?” Specifically, what is the unique effect of the words “but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law”?

The ONLY rational reason for the addition of that final dependent clause is to assert that without it, an office holder convicted and removed from office by the Senate would NOT be “subject to Indictment, Trial, Judgment and Punishment, according to Law.” But that can only mean that office holders—past or present—are NOT “subject to Indictment, Trial, Judgment and Punishment, according to Law” unless and until they have been convicted and removed from office by the Senate.

Were that not the case, then ANY Federal office holder (not just the President) could be prosecuted—and convicted—for ANY action that deprived anyone of their Constitutional rights based on U.S. Code Title 18, section 242 (“Deprivation of Rights under Color of Law.”) Not only does that statute not exempt government officials of any sort, it specifically targets them! That would mean that any Federal or State legislator, President, Governor, judge or prosecutor would potentially be criminally liable for passing or enforcing any law or regulation that was Unconstitutional because it violated the Constitutional rights of one or more individuals—the right to keep and bear arms, for example. And such prosecutions could occur even after the person was no longer in office, even if the person had never been impeached and convicted by the Senate.

I’m betting that the Supreme Court does NOT want to go there, and so will rule (eventually) to grant broad immunity to Presidents—even if it’s not absolute, and even if any such ruling has to wait for the details of the immunity issue to be remanded to and then considered by inferior courts, followed by the ruling(s) of the inferior courts being appealed back to SCOTUS.