On October 3, the South Dakota Democratic Party held a meeting in Chamberlain, and voted to let independent voters vote in Democratic Party primaries.

In 1986 the U.S. Supreme Court ruled that if parties wish to allow independents to vote in their primaries, that is their choice, regardless of what state election law says. That case is Tashjian v Republican Party of Connecticut, 479 U.S. 208. South Dakota election law already acknowledges that parties may invite independents into their primaries, but no South Dakota party has previously done this.