Democrat Theresa Greenfield launched her Iowa Senate bid to unseat Sen. Joni Ernst (R-Iowa) on Monday, a race her party views as a top pick-up opportunity.

Greenfield, who casts herself as "a proud farm kid with farm kid values" and runs a small business, used her campaign launch to slam Ernst for what she says is a failure to rein in lobbying on Capitol Hill.

"All over Iowa, people are getting the short end of the stick from politicians in Washington," Greenfield said. "Joni Ernst told us she'd be different and said she'd to go to Washington to 'make 'em squeal,' but the special interests and corporate lobbyists keep feasting like hogs at the trough."

"In the Senate, I'll give the breaks to working folks by fighting to invest in improving education, supporting small business, and ensuring affordable health care for all Iowans. I'm a proud farm kid with farm kid values, and I'm running for U.S. Senate because I'll never forget who I am, where I'm from, or who I'm fighting for."

Greenfield ran for Iowa's 3rd Congressional District in 2018 but dropped out after she found out that her campaign manager falsified several signatures on petitions qualifying her for the ballot. She is the third Democrat to jump into the race to challenge Ernst, joining businessman Eddie Mauro and lawyer Kimberly Graham.

Ernst's campaign sent out a statement Monday evening highlighting her experience in the Senate and U.S. Army National Guard and defending her efforts to curb the influence of special interest groups.

"Joni looks forward to continuing to take her record as an independent voice that delivers for Iowa to all 99 counties, as she has done" since taking office, Ernst campaign senior adviser Brook Ramlet said in the statement.

Democrats had hoped that freshman Rep. Cindy Axne, who flipped a Republican House seat last year, would run for the Senate, but she declined.

Though Iowa trends strongly Republican in statewide races and voted for President Trump by about 10 points, Democrats view Ernst's seat as a prime opportunity to chip into the GOP's 53-47 Senate majority.

Yet whoever prevails in the Democratic primary will likely face a tough contest to unseat the first-term Republican. A February Des Moines Register poll found that 57 percent of Iowans approve of the job she's doing, her highest mark thus far.

Beyond Iowa, Democrats are eyeing Republican-held seats in Maine, Colorado, Arizona and North Carolina.