(NewsNation) — Minnesota Gov. Tim Walz “can’t wait to debate” Ohio Sen. JD Vance, his opponent for the vice presidency, but only “if he’s willing to get off the couch and show up,” Walz said while making his debut as Kamala Harris’ running mate at a Pennsylvania rally Tuesday. 

“JD Vance literally wrote the foreword for the Project 2025 agenda,” Walz said. “Like all regular people I grew up with in the heartland, JD studied at Yale, had his career funded by Silicon Valley billionaires and then wrote a bestseller trashing that community. C’mon. That’s not what Middle America is.”

Walz began being mentioned as a contender for the spot at the end of July, with Democrats applauding his affable persona, praise among unions and national experience as chair of the Democratic Governors Association. 

Walz’s liberal policy record and decorated background as a congressman and soldier made him stand out as a vice presidential contender.

Walz won his congressional bid in 2006 and served for 12 years before pivoting his career in 2019 to assume the governorship. In that time, he gained recognition as a top Democrat on the House Veterans’ Affairs Committee and the highest-ranking enlisted soldier in congressional history.

After the news that Biden dropped out of the presidential election, Walz threw his full support behind Harris.

“I’m proud to give Kamala my full support and commit to doing everything in my power to make sure she gets elected in November,” Walz posted on X.

Harris doesn’t have much of a relationship with Midwest voters, something that Walz could help her campaign secure as her running mate this November.

Axios reported Walz would add to Harris’ campaign a consistent progressive voice that could help secure white working-class support in Midwestern states.

“In terms of auditioning, (Walz is) doing an exceptional job,” a person familiar with the Harris campaign’s VP conversations told Politico. “He’s got the Midwest grit, the Midwest sensibility and that appeal goes beyond the Midwest.”