For decades, Americans United for Separation of Church and State called its adversaries “religious extremists.” Today, the group has a more specific target: fighting Christian nationalism. The decision to sharpen the language was made by Rachel Laser, the group’s president for the last six years. A Jew and the first religious minority to lead Americans United since its founding in 1947, Laser wanted the group to be more clear-eyed about what she sees as a growing threat to religious pluralism in the United States: the belief that American laws should favor Christian values over those of other religions. But it was not an easy decision for her to make.