Vice President Kamala Harris kicked off a bus tour through Pennsylvania by rallying volunteers in the critical battleground state, as her Republican opponent, Donald Trump, announced plans to ratchet up his cadence of political events in a bid to stall her momentum.

Harris’ trip to Pittsburgh and the city’s surrounding counties ahead of the Democratic National Convention this week in Chicago underscores how crucial the state is to Democrats’ hopes in November, and efforts by Harris — who has surged in the polls since taking over the party ticket for President Joe Biden just weeks ago — to make inroads with White suburban voters who could decide the race.

“We know our country is going to be as strong as our willingness to fight for it, and to fight for what we stand for,” Harris told supporters in Beaver County.

The tour comes as Trump, the Republican nominee, announced plans for a blitz of rallies, press conferences, and interviews in a bid to turn attention back to issues like immigration and the economy where the GOP sees an advantage.

Trump will counterprogram Democrats’ convention with rallies Monday in Pennsylvania, Tuesday in Michigan, and Wednesday in North Carolina. The following day, the former president will head to the U.S.-Mexico border for an event intended to highlight the vice president’s role working on the White House’s immigration policy.

Aides say the Republican will also hold a series of interviews and media availabilities, seeking a contrast with Harris, who has largely shied away from the press in the weeks since capturing the nomination.

That’s in part because Democrats have little desire to disrupt the momentum of the race. A survey released Sunday shows that Harris leads Trump narrowly in a head-to-head matchup, 49% to 45%, among registered voters nationally. The same poll, from the Washington Post, ABC News and Ipsos, showed a dead heat in early July when the candidate was Biden.

In Pennsylvania, Harris is expected to visit a campaign phone bank and local shops, among other stops. The vice president will be joined by her running mate, Minnesota Gov. Tim Walz, along with second gentleman Doug Emhoff and Minnesota first lady Gwen Walz. After the multistop tour, the group is expected to head to Chicago to kick off the week-long celebration of Harris capturing the Democratic nomination.

Campaign officials acknowledge Harris is looking to reconstitute the coalition that delivered the state to Biden and Harris during the 2020 election, where they were also facing Trump. Biden won the state by just over one percentage point, buoyed by both strong turnout from urban liberal voters and by eating away at Trump’s margins in historically conservative counties like Beaver, the exurb to Pittsburgh’s northwest.

One challenge for the vice president is replicating that success without Biden, a native son of Scranton, Pa., who has long highlighted his ties to the Keystone State and who enjoyed support from moderate and elderly White voters. Harris is hopeful that her newly unveiled economic platform, which includes populist provisions such as a subsidy for first-time homebuyers, an expanded child tax credit, and new caps on out-of-pocket prescription drug costs helps to maintain those margins.

“When you believe in ending child poverty, you fight for that. When you believe in what we need to do to lift up the middle class, you fight for the middle class,” Harris said. “These are the things we stand for, and these, therefore, the things we fight for.”

The trip will also be an early test of the Harris campaign’s logistical and messaging prowess, as it seeks to graft the vice president’s vision onto an infrastructure developed for Biden. Her campaign has seven field offices in Western Pennsylvania, and has launched a weekend door-knocking campaign in a bid to harness the enthusiasm Harris has enjoyed since Biden’s exit from the race.