Why JD Vance's plan to follow Kamala Harris and her VP pick on their swing-state tour is a big gamble

• JD Vance is set to follow Kamala Harris for three days as she makes a battleground state swing with her VP.
• Republicans are working hard to halt the momentum surrounding Harris' presidential campaign.

Vice President Kamala Harris is just hours away from embarking on a swing-state tour with her yet-to-be announced running mate, an effort that is poised to be a major turning point for Democratic ticket.

But if Ohio Sen. JD Vance, the GOP vice-presidential nominee, has his way, Harris' time in the spotlight with her vice presidential pick won't be an easy experience.

Vance plans to follow Harris for three days and across four swing states as the presumptive Democratic nominee campaigns with her running mate, according to Politico. The rollout is especially important for Harris as she became the party's standard-bearer less than a month ago following President Joe Biden's exit from the presidential race.

The Ohioan is set to trail Harris in Philadelphia; Detroit; Eau Claire, Wisconsin; and Raleigh, North Carolina. And while Vance won't be headlining rallies, he'll be holding media appearances in the cities alongside voters critical of the Biden-Harris administration.

At first glance, Vance's trip may not seem like a high-stakes effort.

But it's a gamble.

Republicans want to blunt Harris' momentum

In recent months, former President Donald Trump had been leading Biden in most major national polls. And Vance's vice presidential selection was seemingly aimed not at drawing in swing voters — who had been souring on Biden — but on firming up the Republican base.

But Biden's withdrawal from the race and Harris' ability to quickly rally the party around her caught the GOP by surprise. And it sapped any real bump that could have resulted from last month's Republican National Convention.

In recent days, Harris and Trump have been locked in a close race in national and swing-state polls, with the vice president pulling ahead in some of the surveys.

Enter Vance, who wants to halt any sort of sustained momentum for Harris as she stumps with her eventual vice presidential pick.

When Harris appears in key battlegrounds this week, Vance will be there to attack the Democratic ticket on local news and bring out conservative voters to sharpen criticism of Biden's record on issues like the economy and immigration. The senator is seemingly aiming to get ahead of the news cycle to blunt a potential Democratic vice presidential honeymoon period.

Vance's effort could make him even more unpopular

Since joining the GOP ticket last month, Vance's rollout has been a rocky one.

Vance already had a national profile due to his best-selling 2016 memoir "Hillbilly Elegy." But before Vance was elected to office in 2022, he made a raft of controversial statements, and during one notable interview, he deemed some Democratic Party leaders to be "childless cat ladies" who didn't have a stake in the country's future.

Vance's past remarks and MAGA-aligned views on issues like Ukraine (he opposes US funding for the conflict) haven't been a hit with voters. He boasted a minus-5-point favorability rating after the GOP convention. Last month, CNN reported that Vance had a double-digit unfavorable rating with voters in a group of Midwestern states that included his native Ohio.

So Vance's plan to lay into Harris and her running mate will be a tricky balancing act. He doesn't have the highest standing with voters right now, and if Harris taps either Pennsylvania Gov. Josh Shapiro or Minnesota Gov. Tim Walz as her running mate, she'll have an executive by her side with real appeal among working-class voters.

Vance may struggle to define Harris' views

Vance will be looking to draw attention to the GOP ticket when Americans will naturally want to learn more about Harris' running mate.

It'll be a huge fight for attention during a time when Harris could receive another polling bump based on the selection.

Republicans have sought to depict Harris as too liberal for the country and have pointed to her San Francisco Bay Area roots to make their case.

But that argument thus far has not proven to be effective with voters.

A vice presidential pick like Shapiro or Walz — who are both seen as mainstream Democratic choices — could throw cold water on some of the attacks over Harris' ideology.

Vance will surely hammer Harris over her past support for more liberal proposals on healthcare during her 2020 presidential campaign. But Harris now has a record as part of the administration, and she can point to populist achievements like capping the cost of insulin at $35 per month for many Americans on Medicare.

Some voters will applaud Vance's shadow tour of Harris' vice presidential rollout, while others will view it as a stunt. Either way, Vance's itinerary shows that Democrats have all the momentum right now, and Republicans are doing whatever they can to stop it.