Smith v. Allwright: Supreme Court Strikes Down White Primaries, Opening Democratic Party to Black Voters

The Supreme Court ruled 8-1 in Smith v. Allwright that Texas’s white primary system violated the Fifteenth Amendment, striking down one of the South’s most effective tools for excluding Black voters from meaningful political participation. The decision, argued by Thurgood Marshall for the NAACP Legal Defense Fund, overturned the Court’s own 1935 precedent in Grovey v. Townsend and marked a critical turning point in the legal assault on Jim Crow voting restrictions.

Lonnie Smith, a Black dentist from Houston, sued after being denied the right to vote in the Texas Democratic primary. In the one-party South, Democratic primaries determined election outcomes—whoever won the primary won the general election. By excluding Black voters from primaries while technically allowing them to vote in meaningless general elections, Texas maintained the fiction of complying with the Fifteenth Amendment while effectively denying Black political participation.

Justice Stanley Reed’s majority opinion held that political parties conducting primaries are performing a state function and thus bound by constitutional restrictions. The Court rejected Texas’s argument that the Democratic Party was a private organization free to set its own membership rules. When a state gives parties authority to conduct primaries that determine election outcomes, those parties become state actors subject to the Fifteenth Amendment.

The decision immediately threatened white political supremacy across the South. In Texas, Black voter registration surged from 30,000 in 1940 to 100,000 by 1947. Southern states scrambled to find new exclusionary mechanisms. South Carolina repealed all 150 of its primary laws, attempting to make the Democratic Party entirely “private.” Alabama required loyalty oaths supporting white supremacy. Georgia invented the “county unit system” to dilute urban (and Black) voting power.

Smith v. Allwright demonstrated that sustained litigation could crack Jim Crow, but also that each legal victory prompted new evasive schemes. The NAACP’s legal strategy—attacking disenfranchisement piece by piece through the courts—proved both essential and insufficient. Without federal enforcement mechanisms to prevent states from inventing replacement barriers, formal constitutional victories repeatedly failed to translate into actual voting rights for Black Southerners.