The only woman running for Iowa’s open U.S. Senate seat routinely talks about her pistol and her past experience in castrating farm animals, part of what a University of Iowa political science professor calls a “subtle effort” from Joni Ernst to prove she can go toe-to-toe with the power brokers in D.C.

Joni Ernst of Red Oak stresses her experiences as a soldier in the National Guard.

“As someone who has commanded brave Iowans in a combat zone, I know the demands we place on our men and women in uniform,” Ernst tells Iowa audiences.

She touts her status as a member of the Iowa Senate.

“I am the only one here on this stage who has stood up against ObamaCare. I voted no,” Ernst said this past Thursday during a forum with the five other male candidate. “…I want to continue that fight in Washington, D.C.”

And Ernst talks about being a mother and grandmother.

“And as a farmer’s daughter who grew up in southwest Iowa castrating pigs with her dad, I can go to Washington and cut pork,” Ernst says during appearances on the campaign trail.

University of Iowa political science professor Tim Hagle says as a former farm kid himself, he laughs “pretty hard” at that, but Hagle sees the serious message behind the comment, too.

“Saying, ‘Hey, I’m not some frilly kind of a person. I can hang tough with the boys in congress,'” Hagle says.

Dianne Bystrom, the director of the Iowa State University Center for Women and Politics, has done research on the campaign ads of U.S. Senate candidates from 1992 to 2012. Bystrom found the “tough, but caring” strategy was common among female candidates.

“Survey research shows that voters’ question about women candidates is: ‘Are they tough enough for the job?’ Bystrom says, “so you very often see women trying to prove in various ways how tough they are.”

In states like Iowa with rural populations, Bystrom has found female candidates for the U.S. Senate have emphasized farm and ranching experience and their comfort with guns to illustrate their toughness.

“It’s a strategy that we’ve seen not only with Republican candidates, but it’s also with Democratic candidates,” Bystrom says.

In Iowa, Democrats nominated women candidates for the U.S. Senate in 1992 and 2012. Hagle says Democrats in Iowa have been more likely to tout the idea of electing a woman to congress, so Ernst seems to be taking the “subtle” approach.

“By and large, women Republican candidates probably don’t want to make that gender-based argument as directly,” Hagle says, “and so, in a sense, maybe this is a way to do that and kind of let people know that, ‘Hey, I’m running and I want to get out there and mix it up with the guys in the senate.'”

Men far outnumber women in the U.S. Senate. Eighty senators are male and 20 are female.