Charles Ernest Grassley is an American politician serving as the president pro tempore of the United States Senate since 2025, a role he also held from 2019 to 2021. A member of the Republican Party, Grassley is the senior United States senator from Iowa, serving since 1981. He is the dean of the United States Senate. Before becoming a senator, Grassley served eight terms in the Iowa House of Representatives and three terms in the United States House of Representatives.