The 2010 United States Senate election in Iowa took place on November 2, 2010, alongside other elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections in Iowa. The party primary elections were held on June 8, 2010. Incumbent Republican U.S. Senator Chuck Grassley won re-election to a sixth term.
Three Democrats sought the Democratic nomination. Former State Representative and Iowa Department of Transportation official Bob Krause drew attention for implying that Grassley had been in office too long, remarking to supporters in Des Moines: "As a good farmer, Sen. Grassley must recognize that 51 years, or 58 years at the end of his term, is a long time to go without rotating crops." Both Krause and former State SenatorTom Fiegen cited Grassley's support of deregulating the financial services industry as reasons for running. Krause said, "Please remember that Farmer Grassley was one that opened the barn door and let the cow out at AIG," while Fiegen, a bankruptcy lawyer, has made reducing unemployment and tightening regulation of the financial services industry the cornerstones of his campaign.
Former Iowa Democratic Party Chairman Michael Kiernan said that he had recruited trial lawyer Roxanne Conlin to challenge Grassley. Kiernan's virtual endorsement of Conlin prior to her announcement drew the ire of party members, as it is counter to party rules when there is more than one candidate from the party competing in a primary race. Conlin had been criticized for being unwilling to debate her primary opponents, and for being unfamiliar with and unsupportive of her own party's platform.
On health care, Fiegen and Krause supported a public option, while Conlin didn't state a position, which she had been criticized for. Krause and Feigen claimed she supported supply-side economics. She also displayed an unfamiliarity with the Iowa Democratic Party's platform, repeatedly claiming there was no platform for her to support until after the June 12, 2010 convention.
Incumbent Chuck Grassley started the campaign moderately popular, but his approval ratings dropped somewhat during the campaign. However, the seat continued to be considered to be "Safe Republican" by many sources, with CQ Politics noting that Grassley is "one of Iowa's most durable politicians."
Conlin described herself as a "prairie progressive." She supported the recent landmark case of Varnum v. Brien, which legalized gay marriage in the state. She also supported repeal of "don't ask, don't tell."
Before the election, former political advisor John Maxwell claimed that Grassley would have his toughest race since his first U.S. Senate election in 1980, where he defeated incumbent John Culver with 53% of the vote. Grassley won all of his four re-election bids with nearly 70% of the vote against unknown opponents. Grassley won the election with 64.51% of the vote.