Bangladesh, Sept. 21 -- What makes someone American?

For most of the country's history, the answer seemed obvious enough: America was a nation built by immigrants, but immigrants were expected to become Americans. Today, however, that assumption is increasingly contested.

The debate is no longer simply about who enters the United States. It is about what happens after they arrive-and what, exactly, "becoming American" is supposed to mean.

Two competing definitions dominate the argument.

The first is civic nationalism. According to this view, America is fundamentally an idea: a constitutional system based on individual liberty, equality before the law, free expression, religious freedom and democratic self-government. Anyone who embra...