Sen. JD Vance (R-Ohio) and Minnesota Gov. Tim Walz (D) will go head-to-head in the vice presidential debate hosted by CBS News on Tuesday, in what could be a pivotal moment in the race for the White House. Vance, 40, and Walz, 60, haven't duked it out before, but they have taken aim at each other in the weeks since being named the running mates to former President Trump and Vice President Harris, respectively. Vance has taken swipes at Walz's military career, while Walz has targeted Vance's Ivy League pedigree. CBS anchor Norah O’Donnell and correspondent Margaret Brennan will moderate the only vice presidential debate scheduled this cycle, but the network hasn't revealed specific details about the setup of the event. It's expected to last about 90 minutes, beginning at 9 p.m. from the network's broadcast center in New York City. People can watch on local CBS News stations or stream online via CBS News 24/7 and Paramount+. The debate also will air across most major networks, including C-Span and Fox News. The Hill will host a live blog, and its sister network NewsNation will air the event. The Hill/Decision Desk HQ aggregate of national polls has Harris ahead by 4.1 percentage points, but neither candidate has a firm hold on the 270 electoral votes needed to win the White House. Harris and Trump went head-to-head in an ABC News debate earlier this month, but they won't debate again because Trump won't agree to face off against Harris again before Election Day. Some political pundits already are deeming the Tuesday match-up as a crucial one for the Harris-Trump battle. "The veep debate may not be a decisive, but it could be dramatic," Democratic pollster Brad Bannon wrote in a recent op-ed for The Hill. “All the needle needs to be moved is 0.1 percent in either direction, and that could be the difference in four or five states,” Democratic strategist Steven Maviglio recently told The Hill. This is the first election cycle in decades that the nonpartisan Commission on Presidential Debates hasn't organized the debates, typically held on college campuses. News organizations have been working with the campaigns to set up the structure, but specific terms haven't been released for the Vance-Walz match-up.