DES MOINES – Mitt Romney today will pick up yet another major endorsement of the week when South Dakota Republican Sen. John Thune endorses him at a campaign stop in Iowa.

Thune, considered to be a rising GOP star, defeated Senate minority leader and incumbent Sen. Tom Daschle in 2004. Thune’s name was also floated as a vice presidential nominee during Sen. John McCain’s president bid in 2008. And Thune ruled out a presidential run of his own in February, saying in a statement that he had decided to remain in “the trenches” of the Senate.

Romney has received endorsements in the past few days from Sen. Kelly Ayotte, R-N.H., and Rep. Charlie Bass, R-N.H.

Of his endorsement of Romney, Thune wrote today, “The next election will be the most important in generations. We can choose to continue on the same path with four more years of President Obama’s failed policies or we can choose a leader who has the needed experience to lead an economic recovery.”

“Mitt Romney has shown throughout his life in the private sector, as leader of the Olympics, as governor, and in this campaign that he will not back down from difficult challenges,” Thune said. “His plans to revitalize the private sector and restore our country’s fiscal health are drawn from his 25-year career as a conservative businessman. Washington could use these commonsense principles at such a critical time.”

Shortly after the endorsement was made public, Tim Albrecht, communications director for the office of Iowa Gov. Terry Branstad and former Iowa press secretary for Romney’s 2008 campaign, tweeted, “Thune is a huge get. He’s the dragon-slayer who took out Daschle. People don’t forget that.”

Romney, who visited South Dakota in October, said that he is “honored” to have Thune’s support.

“On the issues that I have been fighting for in my campaign – creating a better business environment, lessening the regulatory burden and ending Washington’s spending addiction – Sen. Thune has been a leading voice in the Senate,” Romney said. “He will be a trusted adviser as I bring this message to voters, work to reverse President Obama’s failed policies, and reform Washington.”

Thune serves on the Agriculture, Nutrition and Forestry, Budget, Commerce, Science and Transportation, and Finance Committees. Thune is also chairman of the Senate Republican Policy Committee.