The Iowa Democratic Party (IDP) is the affiliate of the Democratic Party in the U.S. state of Iowa. While existing when Iowa was granted statehood in 1846, it did not gain broad electoral success until the mid-1950s, when demographic changes resulted in many new voters for the party from immigrants, union members, and industrial workers. The party organizes the Democratic Iowa presidential caucuses, which since 1972 have been the first presidential nominating contest in the national process. Current elected officials Democrats hold no seats in the U.S. House delegation. They hold one of the seven statewide offices and currently hold minorities in the Iowa House of Representatives and Iowa State Senate. Members of Congress U.S. Senate None Both of Iowa’s U.S. Senate seats have been held by Republicans since 2015. Tom Harkin was the last Democrat to represent Iowa in the U.S. Senate. U.S. House of Representatives None Statewide offices Auditor: Rob Sand Legislative leadership Senate Minority Leader: Zach Wahls House Minority Leader: Jennifer Konfrst Municipal The following Democrats hold prominent mayoralties in Iowa: Des Moines: Frank Cownie Iowa City: Bruce Teague Dubuque: Brad M. Cavanagh Prominent former elected officials Vice president Henry A. Wallace – 33rd Vice President of the United States, January 20, 1941– January 20, 1945 Governor Harold Hughes – 36th Governor of Iowa, January 17, 1963 – January 1, 1969 Tom Vilsack – 40th Governor of Iowa, January 15, 1999 – January 12, 2007 Chet Culver – 41st Governor of Iowa, January 12, 2007 – January 14, 2011 US Senator Harold Hughes – January 3, 1969 – January 3, 1975 Tom Harkin – January 3, 1985 – January 3, 2015. First elected to the United States House of Representatives in 1974, he served from 1975 to 1985. Iowa caucuses Considered the official start of the presidential election season, the Iowa Caucuses have been the first official votes cast in the Democratic Presidential nomination process since 1972. That year, the Iowa Democratic Party scheduled its caucus to occur before the New Hampshire Primary. South Dakota Senator George McGovern used his win that year to propel him to claim the party's nomination over Maine Senator Edmund Muskie. The Iowa Caucuses would also help Jimmy Carter claim the Democratic nomination in 1976. From 1984 to 1996, the winner of the Iowa Caucus, excluding incumbents, did not win their party's nomination. But in 2008, Senator Barack Obama won the caucus