House Majority Whip Tom Emmer (R-Minn.) said Sunday he expects Sen. JD Vance (R-Ohio), the GOP nominee for vice president, to hold his opponent, Minnesota Gov. Tim Walz (D), accountable on the debate stage on Tuesday. Emmer, who has played Walz in debate prep with Vance, said he thinks the Ohio senator has the advantage on the issues over Walz going into the debate, in an interview with Martha Raddatz on ABC News’s “This Week. "He's going to do a great job," Emmer said in the interview about Vance. "I can tell you, he's got the issues on his side, Martha. He could talk about the economy that Donald Trump fixed and that Harris and Biden broke. He can talk about the border that Trump fixed, and they broke. He can talk about peace and stability around the world, which they don't even have a clue." “Once he understands that Tim Walz is just going to try and deflect and go into this folksy whatever, he’ll hold him accountable. I think JD will do a great job,” Emmer added. Emmer defended Vance when Raddatz pointed out Vance's unfavorable numbers are higher than Walz's, saying, "I think JD is very likable, and I think he's well liked. And I don't buy into these snapshot polls that are being done for a specific reason." Emmer said he has known Walz for years and thinks "once people get to know who he is and what his policies are," they'll see "he's more radical than Kamala Harris." “People do not like him once they get to know him. And JD will expose that on Tuesday,” Emmer continued. Emmer would not detail the extent of his debate prep with Vance, instead saying, "The debate is on Tuesday night, so I'll let your viewers decide that" when asked whether they've had any mock debates. “I'm not going to get ahead of JD and the team. If they want to talk about exactly what we did, when we did it, how many times, they can do that,” he added. “For me, I did my job — or have been doing my job — in helping JD see what it is he’s going to be dealing with on Tuesday night.” Emmer described the way he prepared to play Walz in debate practice. “I've known Tim, oh, probably since he was first elected almost 20 years ago. And I worked with him directly for four years. I spent the last month just going back, all of his old stuff to get his phrases down, his mannerisms, that sort of thing. My job was to be able to play Tim Walz so JD Vance knows what he’s going to see.” The debate will take place five weeks before Election Day: on Tuesday, Oct. 1. CBS News will host the debate, moderated by “CBS Evening News” anchor Norah O’Donnell and Margaret Brennan of “Face the Nation.”