With Rick Santorum out of the Republican presidential field, clearing a path to the nomination for Mitt Romney, the fight to become the party’s standard-bearer is over, right? Well, not entirely. Despite the nearly unanimous view that Mr. Romney will be President Obama’s challenger in the fall, there are still two men — Representative Ron Paul of Texas and Newt Gingrich, the former speaker of the House — who have not yet agreed. In the face of scorn from their peers, they continue to campaign, even if fewer people are paying attention. Both men say they are seeking influence over...