A radio interviewer asked me the other day if I thought bigotry was the only reason why someone might oppose the Islamic center in Lower Manhattan. No, I don’t. Most of the opponents aren’t bigots but well-meaning worriers — and during earlier waves of intolerance in American history, it was just the same.

Screeds against Catholics from the 19th century sounded just like the invective today against the Not-at-Ground-Zero Mosque. The starting point isn’t hatred but fear: an alarm among patriots that newcomers don’t share their values, don’t believe in democracy, and may harm innocent Americans.

Followers of these movements against Irish, Germans, Italians, Chinese and other immigrants were mostly decent, well-meaning people trying to protect their country. But they were manipulated by demagogues playing upon their fears — the 19th- and 20th-century equivalents of Glenn Beck.