By Jeff Zeleny, CNN(CNN) — Sen. Amy Klobuchar launched a Democratic bid for governor on Thursday, pledging to unify her state and move beyond a deadly battle with the federal government over immigration. Tim Walz ended his reelection bid in the wake of a deepening federal investigation into widespread fraud of social service programs in Minnesota. Klobuchar, 65, has long been seen as one of Minnesota’s most popular leaders in one election after another. In the race for Minnesota governor, a crowded GOP field is already engaged in a competitive primary including Lisa Demuth, the speaker of the Minnesota House and highest-ranking Republican in the state. “I don’t like fraud or waste in government – that’s why I went after crime as county attorney,” Klobuchar said.