After wrapping up a Q&A session at a public conference where I presented on the topic of Islam and Christian-Muslim relations to a largely evangelical Christian audience, an older man who was sitting in the back approached me at the podium.

Rather nonchalantly, he asked, “You do know that the Constitution wasn’t written for Muslims, right?”

As we talked, he elaborated on his opinion that the concept of religious freedom does not apply to Islam and Muslims because, he said matter-of-factly, “Islam is not a religion.” At the time, it seemed to me a fringe theory cooked up in the dark corners of the internet or in 6am greasy-spoon breakfast meet-ups.

In short, I could not really believe — given my own biases — that people could actually think that the First Amendment and its promise of religious freedom did not extend to Islam and Muslims in the U.S.

However, far from fringe political theory or radical cultural posturing, this view has found its way into legal briefs, court cases, and political contexts in recent years. In fact, these legal and political perspectives are the fodder for Asma Uddin’s new book When Islam Is Not a Religion: Inside America’s Fight for Religious Freedom.

In this work, Uddin points out that many Americans insist that the religious liberty they so quickly claim for Christianity or Judaism (or other religions beyond the nation’s so-called “Judeo-Christian” heritage) does not extend to Islam and Muslims in the U.S.