My understanding of Wilkinson’s argument is that when a minority party uses their power to create the Supreme Court into a 6-3 ideological entity that consistently rules against the will of the majority, the court’s authority is more likely to be seen as illegitimate be the majority, and that’s a problem.
Here is an except:
When minorities strip majorities of their power to successfully seek redress and assert their will within the system — which is what a stacked 6-3 Republican court majority veto over Democratic unified government could amount to — sooner or later, stymied majorities will seek to protect their rights and interests outside the system. This is what it means for a political system to lose legitimacy — in the grubby, practical, nuts-and-bolts stabilizing sense of “legitimacy.” And that’s profoundly important, because we don’t want citizens to act outside the institutions meant to prevent disagreement from spilling into civil conflict. Avoiding that is the whole damn point. [...]
If a group of ten is deciding where to have dinner, the option that leaves six people disappointed is obviously worse than the option that leaves four people disappointed. The authority of majority rule derives from our shared recognition that it’s better when more rather than fewer people get what they want. It really is that simple.