Interracial marriage is a form of marriage outside a specific social group exogamy involving spouses who belong to different races or racialized ethnicities. In the past, such marriages were outlawed in the United States and in South Africa as miscegenation. It became legal throughout the United States in , following the decision of the U. Virginia , which ruled that race-based restrictions on marriages, such as the anti-miscegenation law in the state of Virginia , violated the Equal Protection Clause of the United States Constitution.
Racial integrity laws were passed by the General Assembly to protect "whiteness" against what many Virginians perceived to be the negative effects of race-mixing. They included the Racial Integrity Act of , which prohibited interracial marriage and defined as white a person "who has no trace whatsoever of any blood other than Caucasian"; the Public Assemblages Act of , which required all public meeting spaces to be strictly segregated; and a third act , passed in , that defined as black a person who has even a trace of African American ancestry. This way of defining whiteness as a kind of purity in bloodline became known as the "one drop rule. From his position as the state registrar of vital statistics, Walter A. Plecker micromanaged the racial classifications of Virginians, often worrying that blacks were attempting to pass as white. Virginia Indians were particularly incensed by the laws, and by Plecker in particular, because the state seemed intent on removing any legal recognition of Indian identity in favor of the broader category "colored.
Though the notion that racial mixing is undesirable has arisen at different points in history, it gained particular prominence in Europe during the era of colonialism. The term miscegenation entered the English language in the 19th century as racial segregation began to become more formalized in the United States. It was used specifically to refer to interracial marriage and interracial sexual relations. Although the term "miscegenation" was formed from the Latin miscere "to mix" plus genus "race" or "kind", and could therefore be perceived as value-neutral, it is almost always used in a negative way, as something to be avoided, punished or outlawed.
In the United States, anti-miscegenation laws also known as miscegenation laws were state laws passed by individual states to prohibit interracial marriage and interracial sex. Anti-miscegenation laws were a part of American law, in some States since before the United States was established. Most states had repealed their bans on interracial marriages by , when the U. Virginia that such laws in the remaining 16 states were unconstitutional.