The nine long faces that stare back in photographs of the U.S. Supreme Court radiate a sobriety intended to convince us that it is a bastion of deliberation, reason and uprightness, walled off from the messy business of politics. Nothing has done more to turn that perception upside-down than the past two weeks of sound and fury over the nomination of Brett Kavanaugh.

Perhaps the perception itself has been part of the problem. From the beginning, the Supreme Court was much more of a political cockpit than the legend of jurisprudential...