On March 13, South Dakota Governor Dennis Daugaard signed HB 1034. It changes the vote test for a party to remain on the ballot. The old law requires a vote of 2.5% for Governor. The new law requires 2.5% for any statewide race.
The only parties on the ballot in 2016 in South Dakota were Republican, Democratic, Libertarian and Constitution. All four of them met this new requirement. The Libertarian Party polled 5.6% for President, and the Constitution Party polled 4.95% for Public Service Commission.
The old vote test had to be met every four years, and the new requirement means parties must pass the vote test every two years. Superficially, then, that is more difficult. But in reality, there are always enough statewide offices on the South Dakota ballot every election year that the change makes it easier, not more difficult, for a party to remain on.