Republican candidate Joni Ernst defeated Democratic Rep. Bruce Braley Tuesday in the race for Iowa’s open Senate seat to replace retiring Democratic Sen. Tom Harkin.

With 94 percent of precincts reporting, Ernst led Braley, a four-term congressman, 52 percent to 44 percent.

Ernst, a state senator and a lieutenant colonel in the Iowa National Guard, first made a splash during the Republican primary with a memorable ad, in which she promised to use her farm experience to make Washington “squeal.” She harkened back to that theme during her victory speech Tuesday.

“It's a long way from Red Oak to Washington, from the biscuit line at Hardees to the U.S. Senate,” she said. "But thanks, thanks to all of you we are heading to Washington and we are going to make them squeal.”

Ernst worked to link Braley to Washington dysfunction, and fended off his arguments that she was too conservative for Iowa. She supports shutting down the Environmental Protection Agency and Department of Education and backed a "personhood" amendment that would outlaw abortion.

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Braley also made a series of missteps during his campaign, from complaining about the lack of gym towels at the Capitol during the partial government shutdown to disparaging Republican Sen. Chuck Grassley as a “farmer who never went to law school.” He also was mocked in the press for a feud he had with a neighbor whose chickens were wandering onto his property.

Braley told his supporters Tuesday night that although he is disappointed, he is optimistic about the future.

“There are a lot of disappointed people tonight including me but were lucky to live in country where we get to be disappointed,” he said.

The Democrats also ran into trouble with Braley’s old House seat in Iowa’s 1st District, which flipped to the Republicans. Republican candidate Rod Blum defeated Democratic state Rep. Pat Murphy in that contest.

Ernst’s election ends Iowa's place among states that haven't elected a woman to Congress or as governor.

The Associated Press contributed to this report.