AMBLER, Pa. — Seeking to capitalize on an outpouring of enthusiasm and an influx of cash, Democratic Govs. Gretchen Whitmer of Michigan and Josh Shapiro of Pennsylvania sought Monday to draw a contrast between Vice President Harris and Donald Trump, warning a packed gymnasium here that he would strip more freedoms from a vast swath of Americans.

The rally in this small suburb outside of Philadelphia was one of the first for the nascent Harris presidential campaign in a hotly contested state both parties hope to take in November. For many Democrats, the enthusiastic crowd exemplified the surge in support for their ticket after President Biden opted to step aside following his disastrous debate with Trump in late June.

The governors spent the afternoon blasting Trump and his running mate, Sen. JD Vance of Ohio, as self-interested, out-of-touch and destructive.

“Donald Trump bragged about overturning Roe v. Wade,” Whitmer said. “He appointed Supreme Court justices who are taking away our rights. He cut taxes for himself and for his buddies, and he tried to overturn an election.”

She then went after Vance, saying he “does not see women as equals. He does not want everyone to have a seat at the table. He’s scared of us. … As Democrats, we want everyone to have a seat at the table. I mean even cat lovers and dog lovers alike.”

The event offered an early look at the themes and messages the party’s likely nominee and her surrogates will roll out over the next three months, including pitting Harris, a former prosecutor, against Trump, a felon. The campaign is casting the election as a choice between freedom and the further erosion of rights. But Monday also served as an informal audition by a pair of Democratic stars rumored to be among those Harris is considering to be her running mate.

Shapiro, taking on a vice-presidential “attack dog” role, described Trump as “a guy who doesn’t love this country” and asked the crowd to remember what it was like living in America during the Trump presidency.

“It was more chaos, less jobs and far less freedom,” Shapiro said. “He had no earthly idea how to be president back then. I’m serious. He didn’t know what he was doing.”

He described Trump as a “dangerous” man who leans into imagery and iconography associated with American values while working to strip Americans of cherished rights.

“While he’s hugging the flag, he’s taking away our freedoms,” Shapiro said. “It’s not freedom to tell our kids what books they can read. That’s not freedom. … It’s not freedom to tell women what they can do with their bodies. That’s not freedom. It’s not freedom to tell people they can go vote — but he’s going to pick the winner.”

Harris’s campaign began a week ago after Biden, facing dismal poll numbers and plummeting party morale, upended the race for the White House by announcing that he would no longer seek a second term.

Biden endorsed Harris, who has long been viewed as his heir apparent. And in less than two days, she announced that she had secured enough delegates to be the presumptive Democratic nominee. Since then, her campaign has touted a huge swell of enthusiasm and donations.

Harris’s campaign announced this weekend that it had raked in more than $200 million since Biden ended his own reelection bid, with two-thirds of that haul coming from first-time donors. And the campaign said it had recruited 170,000 new volunteers in little over a week and is holding 2,300 events to mobilize grass-roots supporters at the beginning of August.

That fervor seemed apparent in Ambler on Monday, where the line to see Shapiro and Whitmer at Wissahickon High School was queued up more than two hours before the speeches were slated to start. Officials estimated the audience at 1,100, the crowd filling the school’s gymnasium and ringing an indoor track overhead.

Gloria Richardson, 72, of neighboring Upper Dublin, said she and her husband had been giving $100 to the Biden-Harris campaign as loyal Democrats. Now that Harris was at the top of the ticket, they plan to give more.

“It’s like Barack Obama again. People feel connected. They feel like they have a stake in this,” said Richardson, who was wearing a shirt emblazoned with a Shapiro slogan. “We’re a visual country. We know that [Biden] had good stuff in his brain, but the visuals were taking over the conversation. That was painful. Now it’s very futuristic. I feel like my grandkids have a stake in this. We’re getting the young people involved again.”

Amid the changes at the top of the ticket, Harris is on an accelerated timetable to pick a running mate. She plans to decide by Aug. 7, in line with the Democratic National Committee’s plans for its official nomination. In addition to Shapiro and Whitmer, Sen. Mark Kelly (D-Ariz.) is considered to be on the shortlist, The Washington Post has previously reported. Both Whitmer and Shapiro hail from battleground states that Democrats need to win in November. North Carolina Gov. Roy Cooper (D), who was under consideration to serve as Harris’s running mate, announced Monday on social media that he was withdrawing his name from contention.

Still, it is unclear what enduring impact Harris’s surge of support will have on the race or whether a week’s worth of momentum will last for another three months.

New Fox News polls in battleground states found Trump and Harris statistically tied in Michigan, Pennsylvania and Wisconsin while Harris led by six points in Minnesota. The campaign announced she will travel to Georgia, another battleground state, on Tuesday.

The Trump campaign bought more than $1.7 million in television ads Monday morning across the major swing states of Pennsylvania, Michigan, Georgia, Arizona, Wisconsin and Nevada, according to the tracking firm AdImpact. The spots, set to start running Tuesday and continue through Aug. 12, are the first major general-election purchase by the Republican nominee’s campaign.

The Harris campaign is planning its own series of adslater this week, its first major purchase, according to a person familiar with the details, who spoke on the condition of anonymity because they were not authorized to discuss the matter publicly.

At Monday’s rally, Beth Staab, a 56-year-old Democratic organizer from Montgomery Township, said that things had grown grim amid her group of Democratic-leaning friends — until everything changed eight days earlier.

“We were in a holding pattern. We all had our tasks to do. We all knew what we needed to do, and yet we were like, ‘I don’t think we can do it,’” she said. They all had qualms over Biden becoming the nominee. “Because we felt as though there were a lot of unanswered questions, and we were afraid to be advocating for something that we were not sure of.”

Though Staab said she feels a deep sense of gratitude and loyalty to Biden, the moment that he withdrew from the race “was like the sun was rising. Everyone was happy. Everyone is motivated.”

Michael Scherer in Washington contributed to this report.