On February 10, 2006, the Mississippi Democratic Party filed a federal lawsuit to obtain a closed primary for itself. Mississippi Democratic Party v Barbour, 4:06cv-29, northern dist. (Greenville). Mississippi is one of the 21 states that doesn’t have registration by party. It’s not clear, if the Democratic Party won its lawsuit, how the party would determine which voters are “really” Democrats. Thanks to Steve Rankin for this news.