List of South Dakota senators, with plenty of pictures and photos. List includes current SD senators and all past United States senators of South Dakota. Since the founding of the United States government, Americans have elected two senators per state regardless of the state's population (unlike the House of Representatives). At first, senators were voted into the US Congress by their individual state legislatures. Today though, senators are elected directly by the people. Each pair of senators serve staggered six year terms, with senatorial elections happening every two years. The most recent senate race was especially exciting due to the democrats' controversial support of healthcare reform and the republicans' regrouping with the support of the Tea Party.