The Republican Party right now is severely lacking in diversity. That is why the Republican senators on the Judiciary Committee have been and still are being incredibly slow to realize they should not confirm Brett Kavanaugh. I'm still not sure whether they will figure it out in time; they may indeed go ahead and confirm him. But because they are such an all-white, all-male club, if they do confirm him, they will do so without properly grasping the full consequences of doing so.
Simply put, it is practically impossible to imagine the Supreme Court continuing to be regarded as a legitimate authority worthy of respect by anything more than 50% of the nation's population. We already have Clarence Thomas, credibly accused of workplace harassment by Anita Hill, and we already have Neil Gorsuch, whose seat should properly have gone to Merrick Garland. That these things have been, to a certain degree, accepted may lead some people to conclude, wrongly, that confirmation of Brett Kavanaugh will also be accepted, even after - what, five now? six? - reported separate incidents of him committing sexually assault. But the difference here is the critical mass to alter the decision-making. With Kavanaugh on the court, the court will be ruling in an extreme far-right way on virtually every case that comes before it. And although that would still upset every left-leaning American even if Kavanaugh were the choir boy he pretended to be on Fox News, being upset by the outcomes of court cases doesn't always lead to considering the court itself illegitimate. What will indeed lead to a good 50% of Americans considering the court illegitimate is the combination of both constant far-right court verdicts and the knowledge that at least two of the justices have been credibly accused of sex crimes plus an additional seat on the court was stolen from Merrick Garland. With all of those factors added together, it will be completely impossible for the court to retain anything resembling its former sheen of legitimacy.
Knowing this doesn't solve the problem, of course. Having 50% of Americans cease to regard the Supreme Court a legitimate doesn't somehow automatically strip the court of its legal power. But it will be a major change that the nation will have to grapple with for quite some time. And the Republican senators who will make the decision about whether to confirm Kavanaugh or not do not even see it coming.