 Race and ethnicity differ strongly in the level of agency that individuals exercise in choosing their identity. Individuals rarely have any choice over their racial identity, due to the immediate visual impact of the physical traits associated with race. Individuals are thought to exercise more choice over ethnic identification, since the physical differences between ethnic groups are typically less striking, and since individuals can choose whether or not to express the cultural practices associated with ethnicity. So an individual who phenotypically appears white with ancestors from Ireland can more readily choose whether to assert their Irish identity (by celebrating St. Patrick’s Day) than whether to choose their white identity (Cornell and Hartmann 1998, 29–30). Moreover, Mary Waters (1990) argues that the high level of intermarriage among white Americans from various national ancestries grants their children significant “ethnic options” in choosing with which of their multiple heritages to identify. Waters (1999) and Philip Kasinitz (1992) document how phenotypically black West Indian immigrants exercise agency in asserting their ethnic identity in order to differentiate themselves from native-born African Americans, but discrimination and violence aimed at all Black people, regardless of ethnicity, strongly constrains such agency.The greater constraints on racial identity stem from the role of informal perceptions, discriminatory social action, and formal laws imposing racial identity, such as Census categorization (Nobles 2000), the infamous “hypodescent” laws, which defined people as black if they had one drop of African blood (Davis 1991), and judicial decisions such as the “prerequisite cases,” which determined whether specific immigrants could be classified as white and thus eligible for naturalized citizenship (Lopez 1996).