California is poised to become the first state to outlaw discrimination based on a person’s caste. The system of social stratification, which dates back thousands of years, has been outlawed in India and Nepal for decades. Amy Qin, a correspondent who covers Asian American communities for The Times, explains why so many believe a prejudice that originated on the other side of the globe now requires legal protection in the U.S.  — and why so many are equally convinced that it would be a bad idea. Guest: Amy Qin, a national correspondent covering Asian American communities for The New York Times.