> At least with respect to the President’s exercise of his core constitutional powers, this immunity must be absolute. As for his remaining official actions, he is entitled to at least presumptive immunity.

Article 2, which talks about the president's powers, is vague and has not been stress tested to the same extent it's likely to now be (it seems like there will be a lot of debate around minutiae for years, just based off the trump presidency and charges brought).

As such, the phrase "exercise of his core constitutional power" is significantly less straightforward than it might seem at first glance.

If you read through the ruling, a lot more questions arise than answers. And Sotomayor's dissent only highlights how they don't know themselves. And it's not as though it was clear before this ruling. It was unclear, and this ruling says very little in practice.