Why do some people consider the contemporary Supreme Court “illegitimate”?
When I first heard one politician describe the Supreme Court as illegitimate, I thought they were biased in that they did not like the Supreme Court's rulings, so they subconsciously selected a belief with the teleological aim of having a reason to invalidate the court.
However, since then I have heard some more general arguments that the Supreme Court is a flawed system in that it doesn't perform what it theoretically appears it was supposed to.
Is this true? And why?
For example, I heard that Donald Trump was able to change the political constitution of the Supreme Court by adding seats to it. If this is easily done, why hadn't other Presidents done so before? Could Biden do the same thing now?
I have heard someone say that the Court isn't supposed to be a political body, but is supposed to neutrally interpret the Constitution. But is there any demarcable difference between having an interpretation of the law of the land and having some kind of subjective political worldview?
Given the actual legal theory underpinning what the intended role or purpose of the Supreme Court is, is there actually an infrastructural error in the current Court system causing it to do the wrong thing? What would the solution be, in terms of rules? Or is the Supreme Court perfectly in alignment with its intended function - people selected by elected officials to decide what is right and wrong in a society?