In the current laws you mean, dictatorships usually start by throwing current laws out of the window. Not that I believe Trump would do that, but it is not unheard of in other parts of the world
They can and they did. What the tariff decision shows is simply that, on very specific topics (in this case, big business), their base is significantly split: on one side the populist masses, on the other the wealthy elites. When the chips are down, the current USSC is connected the latter more than to the former, and will vote accordingly.
Start to worry of the Republicans start talking about expanding the Supreme Court to add their own to it