The modern confirmation process for the Supreme Court is full of rules: the "Ginsburg Rule," the "Biden Rule," the "Reid Rule" and the "McConnell Rule." Often their definitions and their relevance are hotly contested. What isn't contested is that the court itself has a widely recognized and easily understood rule: the "rule of four." That rule is key to understanding the full impact of confirming Judge Brett Kavanaugh to the court.
The rule of four holds that for the court to grant certiorari to hear and decide a case, four of its members must vote to do so.