... And in S. Dakota

Unlike most of this year's primaries, South Dakota is a genuine toss-up. Different polls have both Hillary Clinton and Barack Obama leading by double digits. Politico focuses on things to watch for:

• Split time zones: The western half of the state is an hour behind the eastern half; results won't be revealed until all polls close at 8pm CT.

• A late night: Ballots are transported to and counted at county auditor's offices, some more than 2 hours from polling places.

• The Native American vote: Native Americans are South Dakota's largest minority group, with 8.5% of the population.

• Sioux Falls and Minnehaha County: The state's biggest city and the surrounding county are vital to Democrats in the general election.

• Turnout: The secretary of state predicts 40% to 50% of the state's 195,000 registered Democrats; campaign aides expect even more.

(More South Dakota stories.)