SIOUX FALLS, S.D. -

Sen. John Thune has officially given his acceptance speech and will serve a third term in the U.S. Senate.

"I will always listen. My office is always open," Thune says while giving his speech Election night.

The Associated Press declared the incumbent the winner of South Dakota’s U.S. Senate race. Democrat Jay Williams is Thune’s opponent for the Senate seat.

He is seeking his third term in the Senate, and is currently the third highest ranking Republican in the Senate. He is the highest ranking Republican senator in South Dakota history.

Thune first ran for Senate in 2002, when he lost to incumbent Democrat Sen. Tim Johnson. Thune later clinched a seat in the Senate in 2004 when he beat Senate Minority Leader Tom Daschle, with 51 percent of the vote. In 2010, he ran unopposed.

He has served three terms in the U.S. House of Representatives from 1996 to 2002.

U.S. Sen. John Thune (R-S.D.) issued the following statement on his re-election to the U.S. Senate:

"Serving the people of South Dakota in the U.S. Senate has been one of the greatest privileges of my life, and I'm humbled by the opportunity to continue fighting for them in Washington, D.C.," said Thune. "The Republican-led Senate has accomplished a lot of important things over the last few years for the American people, and no matter which party holds the majority next January, there's still a lot of hard work that lies ahead. As U.S. senator, I've always worked to put South Dakota's interests first, and that commitment to our great state will never change.

"No run for public office is won alone, which is why I want to thank Kimberley, Brittany, and Larissa for being my biggest supporters over the years. My family has grown quite a bit since my last election to the Senate. I'm blessed to have two strong, hard-working sons-in-law, a granddaughter, and another grandchild who's on the way. It's because of my family's love and support that I'm continually inspired to serve."

Thune was elected to the U.S. Senate in 2004 after defeating then-Minority Leader Tom Daschle and was re-elected in 2010, an election in which he ran unopposed.

During the 114th Congress, Thune serves as chairman of the Senate Committee on Commerce, Science, and Transportation, which has jurisdiction over rail transportation, among other areas. He also serves on the Senate Committee on Agriculture, Nutrition, and Forestry and the Senate Committee on Finance. Thune is also chairman of the Senate Republican Conference, making him the third-ranking Republican in the U.S. Senate.