The recent Supreme Court ruling crowns the President as King of the USA though. From AP:
If "communications with agency officials" is enough to make something a public act... then all the "killing your political rival for whatever purpose" brought up by commentators and even by Justice Sotomayor is theoretically covered. Hypothetically, Biden (or Trump, if elected) could "communicate with some government agency" to have a SEAL Team waiting in a water hazard on a golf course, their opponent frequents, to remove a clear danger to the "democracy" (but more Kingdom of the US, now).
All hail King and Kingdom of the USA, where prosecution is now toothless against Presidents committing acts officially. Just be in the office, talk to somebody in a government office, put whatever you want in writing, and stamp it with a red "official" stamp.
Jokes aside: the specificity of those rulings is deliciously corrupt. From the same article:
Sotomayor pointed to historical evidence, from the founding fathers to Watergate, that presidents could potentially face prosecution. She took a jab at the conservative majority that has made the nation’s history a guiding principle on issues like guns and abortion. “Interesting, history matters, right?”
Then she looked at the courtroom audience and concluded, “Except here.”
The majority feared that the threat of potential prosecution could constrain a president or create a “cycle of factional strife,” that the founders intended to avoid.
Sotomayor, on the other handed, pointed out that presidents have access to extensive legal advice about their actions and that criminal cases typically face high bars in court to proceed.
“It is a far greater danger if the president feels empowered to violate federal criminal law, buoyed by the knowledge of future immunity,” she said. “I am deeply troubled by the idea ... that our nation loses something valuable when the president is forced to operate within the confines of federal criminal law.”