Rep. Ken Buck says he won't run for Senate Alex Brandon/AP Rep. Ken Buck, R-Colo., listens during a House Judiciary Committee markup of the articles of impeachment against President Donald Trump, on Capitol Thursday, Dec. 12, 2019, in Washington. (AP Photo/Alex Brandon) and last updated 2021-01-28 21:28:51-05 DENVER â U.S. Rep. Ken Buck said Thursday he will not run for U.S. Senate in 2022. In a tweet, Buck, a Republican from Windsor who represents Coloradoâs 4th Congressional District, said he was "humbled by the interest and support." I am humbled by the interest and support I have received to pursue a potential Senate bid, however I will not be running for U.S. Senate in Colorado.