When Harry Truman gave the go ahead to drop atomic bombs on Hiroshima and Nagasaki, it killed as many as 220,000 civilians. Should Truman have been prosecuted for a war crime? Under the Constitution, Truman as President was performing his duty as Commander in Chief of the armed forces. There's little question that the decision was part of his official duties, and most believe Truman was motivated by his desire—based on the information available to him at the time—to reduce the number of American casualties needed to end the war.
Six million European Jews died in the Holocaust. Roughly one in six died at Auschwitz-Birkenau, most in mass executions with Zyklon B, a form of gaseous cyanide dropped into enclosed chambers filled with hundreds of newly-arrived prisoners who were told they were getting a shower before being sent to new homes. Twenty-two thousand Romani, 70,000 Poles, and 14,000 Soviet POWs were also murdered there. Even more disturbing, Nazi "scientists" like Josef Mengele carried out sadistic experiments on non-consenting subjects, many of them children (Mengele had a fascination with Romani and Jewish twins). Auschwitz-Birkenau was a horrific war crime carried out on an unprecedented scale. There's also little question that Hitler was acting in his official capacity as Chancellor of Germany when he approved the complex's transformation from Polish prisoner of war camp to main cog for the "Final Solution" in 1942.
Purely on the basis of whether or not they were official acts, it's hard to distinguish between the decision to drop Fat Man and Little Boy and the creation of Auschwitz-Bierkenau. But although some disagree, history hasn't had much difficulty distinguishing between Truman's difficult executive decision and Hitler's crime against humanity. For most of us, it comes down to motive.
This comports with a long tradition in American criminal law, Socratically drilled into every first year law student. A crime has two components: Actus Rea and Mens Rea or guilty act and guilty state of mind. For example, if you shoot someone in self-defense or to save someone else, it's not murder. If you break into a store or a home in an emergency at night and take something to save a life, it's not necessarily burglary. If you authorize your lawyer to pay off an adult movie star to cover up the fact that you had sex with her shortly after your wife gave birth to prevent voters from finding out about it, the prosecution must still show that you knew about it and did it to impact an election or serve some other legally impermissible purpose. Traditionally, this has been true whether you're President Homelander or a Hughie without 24-hour super powers.
Mens Rea has historically presented difficulties for prosecutors, especially when it involves mental illness, addiction, or—in one infamous case—the ingestion of large quantities of Twinkies. Fwiw, "official capacity" has long been a part of the mens rea calculation. When a police officer shoots the wrong suspect, an ambulance driver runs someone over, or a pharmacist fills the wrong prescription, the relationship of the "act" to their job is always central to determining whether or not the individual had the necessary mens rea to support criminal prosecution. Motive serves as the easiest way to tell the moral difference between mass killings like Fat Man and Little Boy and Auschwitz. Non lawyers don't ask whether it was part of the job; we ask why Truman or Hitler did whatever they did. Was there a legitimate purpose, a less troubling alternative; was it in the nation's interest as opposed to the executive's self interest, say in overturning an election he lost or in taking classified documents and inexplicably refusing to return them when requested to do so?
Possible Presidential criminality hasn't been limited to Truman, and it hasn't always been straightforward. Washington, Jefferson, and even Ulysses Grant owned slaves, certainly a crime today unless you're outsourcing it to make basketball shoes, but legal then. Jackson defied a Supreme Court order when he condemned the Cherokee to the Trail of Tears. Lincoln suspended habeas corpus. FDR interned thousands of Japanese-Americans. Obama authorized drones that sometimes killed civilians in other countries. Reagan's responsibility for Iran-Contra came down to mens rea: he should have been aware of it, but somehow—possibly due to incipient dementia— wasn't. Nixon, of course, was pardoned before any prosecution could have gotten underway. For more than 250 years, America has found a way to sort it out, and it's usually been to give deference to Presidential motives—Jackson and Nixon being perhaps the most interesting exceptions, pre-Trump.
In Trump vs. US (2024), Harlan Crow's Supreme Court not only gave any future Presidents with the initials DJT immunity, or at least the presumption of immunity, for "official" acts, they added a peculiar layer by turning custody of the "motive" baby over to "official act."
In dividing official from unofficial conduct, courts may not inquire into the President's motives. Such a "highly intrusive" inquiry would risk exposing even the most obvious instances of official conduct to judicial examination on the mere allegation of improper purpose (Trump v. US).
Here's the problem with that upside down flag of a majority opinion. Under Article II, the President's official duties include executing and enforcing laws created by Congress. If you ever watched the West Wing, you grasp how that encompasses a near infinitely broad range of Presidential actions, receiving oral sex from one of your interns in the Oval Office being one of the few clear exceptions. Had he been prosecuted, Nixon could have claimed he was simply protecting national security when he assented to that psychiatrist's office break-in. When Hitler authorized Auschwitz, I suspect he would have (if he'd been President of the US and it had happened more recently) a very strong "official act" defense based on his duty to enforce the array of anti-Semitic and anti-Romani laws he'd put in place.
The Trump Presidency turned the West Wing into a Breaking Bad sequel with sprinklings of Sopranos dialogue, though Saul Goodman would surely have done a better job than Rudy Giuliani. Yet, most of those impeachable acts likely had some color of being "official."
Many worry the Court essentially made the President a king instead of an elected citizen, but it's arguably worse. Few western kings post Magna Carta have enjoyed so extreme a form of immunity from angry subjects/citizens; see Charles I, Louis XVI, Maximillian I, and Nicholas II. In the meantime, Article II does include the Presidential power to grant pardons. What if a President pardons someone—let's randomly call the convicted criminal Paul Manafort, Michael Flynn, or Roger Stone for the fun of it—who helped the President cover up a crime or hid evidence that might have resulted in his impeachment? Does the President's motive maybe matter a bit more than whether the pardon was one of his official duties?
If you're deciding to kill 220,000 civilians or two-thirds of the Jewish population of Europe and 60% of its Romani people, you sure as hell should be worrying about the possibility of being criminally prosecuted. Personally, I don't think Truman committed a criminal act, but I'm glad his decision wasn't any less difficult. Basically, the Federalist Society's Court just "protected us" by making it harder to prosecute some future Hitler. We can only pray a guy who talks about putting undocumented immigrants in detention camps, whose own campaign materials (since deleted) referred to a "Reich," and who wants to use the military against his domestic enemies, doesn't get elected again, and if he does, by some miracle he doesn't turn out to be another Hitler.
