Sociologist Stephen Klineberg has stated that U.S. immigration laws prior to 1965 clearly "declared that Northern Europeans are a superior subspecies of the white race".[42][a] The Immigration and Nationality Act of 1965 opened entry to the U.S. to non-Germanic groups, and significantly altered the demographic mix in the U.S. as a result.[42] With 38 U.S. states having banned interracial marriage through anti-miscegenation laws, the last 16 states had such laws in place until 1967 when they were invalidated by the Supreme Court of the United States' decision in Loving v. Virginia.[43] These mid-century gains had a major impact on white Americans' political views; segregation and white racial superiority, which had been publicly endorsed in the 1940s, became minority views within the white community by the mid-1970s, and continued to decline in 1990s' polls to a single-digit percentage.[44][45] For sociologist Howard Winant, these shifts marked the end of "monolithic white supremacy" in the United States.[46]