Jackson v. Allain is a class action lawsuit that challenged Mississippi electoral law on the basis of racial discrimination.

In March 1984, the Center for Constitutional Rights (CCR) filed a federal class action lawsuit that challenged the Mississippi runoff primary law. The law required candidates in the first primary to win a majority of the votes in order to become the party nominee. If no person received a majority, the two candidates who received the most votes would then participate in a runoff primary to determine the winner. Because of the long history and continuing practice of white racial bloc voting against Black candidates in Mississippi elections, such a requirement discriminates against Black candidates who often won the first round but inevitably lost when facing white opponents in second primaries.

A motion to dismiss the suit was denied. The case moved to discovery, a massive undertaking involving the identification and analysis of every county municipal and district election where Black candidates competed in a runoff.