You could well be right, but I have a hard time believing that any court - even this grotesquely corrupt one - would attempt such rulings.

gestures broadly

Have you been paying attention lately?

So far, while obviously a significant threat, their immunity rulings have actually been broadly in line with established precedent. And they specifically stated that the precise definition of an “official act” was something that was going to have to be worked out in future rulings.

Here's the problem. Attempting to prosecute someone based on that logic borders on entrapment. Based on the way the ruling is worded, Trump could call Seal Team 6 tomorrow and "tell them to take out . Oh, and by the way, take out Dolly Parton on the way there. " , and nobody could do anything about it. Since he was in the midst of carrying out an official duty, he can't even be asked about the contents of the phone call, let alone if he ordered them to take out Dolly Parton. " Sure, the Supreme Court may very well rule that it was not an official act....years from now, after it's made its way through the rest of the court system. But you can't go back and charge someone with a crime for committing an act that was perfectly legal when it was committed. And right now, based on the wording of the Supreme Court ruling, the President would be absolutely immune from even being investigated for it, let alone prosecuted -- until they say otherwise. Which would be fine for whoever is #2 on Trump's hit list, but it would still suck to be Dolly Parton.

Even with as cynical as I am, I find it hard to believe that they actually intend to rule that anything that might be done in the midst of carrying out some entirely and completely unrelated official act is afforded the same protection as that official act. That would rather obviously make it so that the president could, for instance, pause in the middle of signing a bill and do literally anything - absolutely anything at all - and be entirely immune from any and all consequences.

Yes - it is possible that they’ll rule that way, but again, even as cynical as I am, I can’t imagine that they actually will, if for no other reason than that that would empower the president to order the summary execution of all Supreme Court justices.

That's pretty much exactly what they said would happen. They spelled it out in great detail. If the President is engaging in an official act, he cannot be investigated for it, and the act and anything related to it cannot be used as evidence against him, even if it's evidence of an unrelated crime. Which means yes, right now he can literally pause in the middle of signing a bill, order the military to nuke Wisconsin because he hates cheese, finish signing the bill, and nobody can touch him.