For a glimpse of how venomous and debased the discourse about Islam has become, consider a blog post in The New Republic this month. Written by Martin Peretz, the magazine’s editor in chief, it asserted: “Frankly, Muslim life is cheap, most notably to Muslims.”

Mr. Peretz added: “I wonder whether I need honor these people and pretend that they are worthy of the privileges of the First Amendment, which I have in my gut the sense that they will abuse.”

Thus a prominent American commentator, in a magazine long associated with tolerance, ponders whether Muslims should be afforded constitutional freedoms. Is it possible to imagine the same kind of casual slur tossed off about blacks or Jews? How do America’s nearly seven million American Muslims feel when their faith is denounced as barbaric?

This is one of those times that test our values, a bit like the shameful interning of Japanese-Americans during World War II, or the disgraceful refusal to accept Jewish refugees from Nazi Europe.