This book explores public opinion about being and becoming American, and its implications for contemporary immigration debates. It focuses on the causes and consequences of two aspects of American identity: how people define being American and whether people think of themselves primarily as American rather than as members of a panethnic or national origin group. Importantly, the book evaluates the claim – made by scholars and pundits alike – that all Americans should prioritize their American identity instead of an ethnic or national origin identity. It finds that national identity within American democracy can be a blessing or a curse. It can enhance participation, trust, and obligation. But it can be a curse when perceptions of deviation lead to threat and resentment. It can also be a curse for minorities who are attached to their American identity but also perceive discrimination. The notion of American identity is a predisposition that the government has good reason to cultivate, but also good reason to approach with caution.