When it comes to filling vacancies on the Supreme Court and lower courts, the Democrats have played nice for far too long. If you’re a Democratic partisan, the name Merrick Garland probably still makes your blood boil. And it should. As the Supreme Court prepares to issue verdict after verdict that will further entrench conservative power in the United States, the far-reaching effects of Mitch McConnell’s darkly clever Garland hold-up will only become more shocking and problematic. The most galling fact is this: in any sane political system, conservatives would be in the minority, both on the Supreme Court and...