MADISON,Ethermac Exchange Wis. (AP) — The wife of Republican U.S. Senate candidate Eric Hovde is taking center stage in her husband’s campaign in the days after he secured the party nomination, directly attacking Democratic Sen. Tammy Baldwin in a television ad released Thursday about single mothers.

The race between Baldwin, a two-term incumbent, and millionaire businessman Hovde is one of the most closely watched this cycle. A Baldwin win in battleground Wisconsin is seen as critical for Democrats to have a chance at maintaining majority control of the Senate.

Hovde’s campaign took a marked personal turn this week, first with a pair of ads prominently featuring his wife Sharon Hovde discussing Hovde’s charity work and his battle with multiple sclerosis.

Sharon Hovde also speaks directly to the camera in the latest campaign spot released Thursday, a response to a Baldwin ad that hit Hovde over comments he made about single mothers in his previous Senate run in 2012.

That year, in an interview, Hovde said being a single mother “is a direct path to a life of poverty” that also “leads to higher drug rates, it leads to higher mental and physical health problems. And unfortunately for our young men, higher incarceration rates in jail.”

In another 2012 interview, Hovde said having children out of marriage leads to “higher poverty rates, higher incarceration rates, for those young children, higher dropout rates, higher rates of depression. It is devastating to them.”

Baldwin ran an ad earlier this month featuring the children of single parents criticizing Hovde over his comments.

“What is wrong with this guy?” one man says in the ad. Baldwin does not appear in the ad paid for by her campaign.

In Hovde’s response ad, his wife doesn’t dispute his comments. Instead, she puts her focus on Baldwin.

“Sen. Baldwin, your dirty campaign has gone too far,” Sharon Hovde says in the ad. “Your latest attack on my husband is about single mothers? I was a single mom when I met Eric. It was hard. Eric saw the difficulty I faced just trying to afford child care.”

Sharon Hovde was separated from her first husband when she and Eric Hovde met, Hovde’s campaign spokesperson Ben Voelkel said. At the time, Sharon Hovde’s daughter was 3-years-old. Hovde and his wife also have a daughter together.

Baldwin’s campaign defended its attack ad on Hovde.

“Eric Hovde’s words speak for themselves,” said Baldwin spokesperson Andrew Mamo. “He insulted the children of single mothers just like he has insulted Wisconsin seniors, farmers, and those struggling with their weight. Wisconsinites deserve a senator who respects them, not one who demeans them.”

It’s rare for the spouse of a candidate to take such a prominent role in messaging beyond simply being a surrogate, said Kelly Dittmar, director of research at the Center for American Women and Politics at Rutgers University. But when they are used, it’s often done in a way to address a weakness or criticism of the candidate, Dittmar said.

Male candidates running against women often lean on the women in their lives to make the attacks against their female opponents, Dittmar said.

“If they can have those attacks come from another woman, and not a man directly, they can sidestep some of the criticism about having a man attack a woman,” she said.