We've made it very clear for decades that the President can commit acts of war without declaring it. Syria, Lybia, Iraq, Afghanistan, and dozens of other hotspots around the world.
Congress hasn't declared war after WWII. I suppose that's why you used the euphemism "congressional authorization"; instead of what was intended by the folks that wrote the constitution -- a declaration of war.
But assasinating private citizens a ok? So Biden can order the assassination of Trump? Even if you claim as someone else that you can’t violate someone’s constitutional rights within an official act, we have already killed US citizens abroad via drone strikes. So if Trump is in some foreign country we can drop an a-bomb and claim it was to kill some terrorist & that’s a ok?
The minority points out that official acts was already a defense. The majority opinion here claims that it’s an absolute immunity and even motivation is impervious to this immunity claim. This is a serious undermining of the rule of law in a substantial way and paves the way for the US to have a dictatorship at some point in the future.
So first, the distinction between official acts and unofficial acts isn’t actually defined and even Robert’s admits this ambiguity is going to be a problem:
> Determining which acts are official and which are unofficial “can be difficult,” Roberts conceded. He emphasized that the immunity that the court recognizes in its ruling on Monday takes a broad view of what constitutes a president’s “official responsibilities,” “covering actions so long as they are not manifestly or palpably beyond his authority.” In conducting the official/unofficial inquiry, Roberts added, courts cannot consider the president’s motives, nor can they designate an act as unofficial simply because it allegedly violates the law.
Basically the President has a presumption that his behavior is an official act unless it’s egregiously outside his powers but there’s also no way to really investigate it. Oh and it’s also combined with the unitary executive theory popular on the right which holds that the president basically has absolute power over all executive agencies and a growing interpretation of the powers of the president (under both parties) which is a scary scenario.
And given that the dissenting opinion from SCOTUS justices literally raises the exact scenario you’re assuming is unofficial, so dismissing it out of hand seems overly bold:
> 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.
You can disagree with the dissents, but even Justice Barrett outlines some very serious problems with the reasoning in the majority opinion while Justice Thomas says they should go further and completely rule Jack Smith’s investigation unconstitutional outright.