Since the entire purpose of a law is to 'intrude on the authority and function' of a criminal, it's almost a tautology. If the president does it, it's not a crime.
It's made worse, though, because this bunch of corrupt assholes leaves a loophole. Despite their absolute-sounding language, they say that it might be okay to interfere with a president. And they say that they will decide, based on no expressed principles, when that occurs. Would this court find a prosecution less likely to interfere with the "authority and function" of a Democratic president? Could be.
Actually, the court says that the presumption of immunity does not apply to unofficial acts. I guess that might mean that a president could, after being out of office, be charged with theft if he left a restaurant without paying. Whether that's the case, however, would also be decided by the new king-makers of the court.
And they make clear that it's very unlikely that a president is ever unofficial. They explain that talking to the public is presumed to be official. If a government official is involved, it's official. They make clear that it really would have to be theft in a restaurant and not much more.
For good measure, they also categorically exclude official acts (determined by them) as evidence of a crime. The example in the dissent is, a bribe having been received, the discussion with the government person implementing the purchased activity is official and cannot be brought into evidence.
The dissent reminds us that the Framers were explicitly clear that the president is subject to law. They saw no reason to think that the president should not do his or her job with a clear eye on what is legal or how this could reduce the effectiveness of governance.
The majority says that it is important that a president need never fear pernicious prosecution for fear of political retribution, i.e., what Trump wants to do. The dissent observes the obvious fact that every prosecution has to get past a judge and for a president, there would be grand juries, interlocutory appeals out the ass, trials, appeals, all of the structure of justice that would stand in the way of abuse.
Justice Barrett, who is showing signs of decency, concurs with the decision but disagrees with its main conclusion. She would, instead, create a premise for pretrial appeal (interlocutory judgment) to determine if charges were applicable to the president. She doesn't discuss the majority premise, "must be immune," but she disagrees with the prohibition on using evidence derived from official acts and that makes me think she might be choosing not to rock the boat in a decision where her vote is not dispositive.
Justice Sotomayor is outraged and brings us to the conclusion that I think is correct: "The President of the United States is the most powerful person in the country, and possibly the world. When he uses his official powers in any way, under the majority's reasoning, he now will be insulated from criminal prosecution.
Orders the Navy's Seal Team 6 to assassinate a political rival? Immune. Organizes a military coup to hold onto power? Immune. Takes a bribe in exchange for a pardon? Immune. Immune, immune, immune.
Let the President violate the law, let him exploit the trappings of his office for personal gain, let him use his official power for evil ends. Because if he knew that he may one day face liability for breaking the law, he might not be as bold and fearless as we would like him to be. That is the majority's message today."
I dissent.