President Trump appears to be on course to give conservatives a sixth vote on the Supreme Court, after several Republican senators who were previously on the fence said they would support quickly installing a replacement for Justice Ruth Bader Ginsburg. In our interview today with Marjorie Dannenfelser, president of the anti-abortion Susan B. Anthony List, she says she senses a turning point. “No matter who you are, you feel the ground shaking underneath,” she said. “I’m feeling very optimistic for the mission that our organization launched 25 years ago.” In pursuit of that mission, the Susan B. Anthony List struck a partnership with Mr. Trump during the 2016 election. The group supported his campaign and provided organizational backup in battleground states in exchange for commitments that he would work to end abortion rights. Ms. Dannenfelser described the partnership as “prudential.” “Religious people use that term quite a lot because it acknowledges a hierarchy of goods and...