I have spent the last several years learning—the (very) hard way—a lesson that most Americans still have not learned: the courtroom has become the principal battlefield of American politics. And on that battlefield, the Left arrived with an army. The Right brought a checkbook and a prayer. That ends now. Last week, the Oversight Project announced the launch of a new law firm—a salaried, in-house, battle-ready legal outfit whose mission can be st…