RIPON, Wis. — Former Republican congresswoman Liz Cheney joined Vice President Kamala Harris on Thursday in Ripon, Wis. – known as the birthplace of the GOP – to campaign against former president Donald Trump in the Democratic nominee’s most emphatic display of cross-party support yet.

Cheney, who endorsed Harris last month, came out to chants of “Thank you, Liz!” and warned against returning Trump to power as he continues to deny his 2020 reelection loss, saying the United States “faces a threat unlike any we have faced before.”

“We cannot turn away from this truth,” Cheney said, surrounded by American flags and red, white and blue signs reading “Country Over Party.” “In this election, putting patriotism ahead of partisanship is not an aspiration. It is our duty.”

“Thank you for your support and your leadership – and your courage,” Harris said onstage with Cheney afterward at Ripon College, a small liberal arts school.

Harris has been making an growing push to showcase GOP support with just over a month until the November election, looking to attract Republicans who are especially disillusioned with Trump over his efforts to reverse his 2020 loss. Cassidy Hutchinson, a former Trump White House aide who was a star witness for the committee that probed the Jan. 6, 2021, assault on the U.S. Capitol, endorsed Harris on Wednesday.

The Harris-Cheney event came amid a week during which the issue of Jan. 6 has returned to the forefront of the presidential race. Trump’s running mate, JD Vance, refused to admit during a debate Tuesday that Trump lost the 2020 election, prompting Democratic vice-presidential nominee Tim Walz to call it a “damning non-answer.”

Then, on Wednesday, a court filing was unsealed that laid out the most extensive evidence yet in federal prosecutors’ case that Trump interfered with the 2020 election. The filing painted Trump as indifferent as rioters stormed the Capitol and described how he told an aide “So what?” when informed security measures had to be taken to protect his vice president, Mike Pence.

Cheney recounted Trump’s alleged comment about Pence to the Ripon crowd, eliciting boos. She said Jan. 6 showed that there is “not an ounce – not an ounce – of compassion in Donald Trump.”

“He is petty, he is vindictive, and he is cruel,” Cheney said, “and Donald Trump is not fit to lead this good and great nation.”

Vice President Kamala Harris makes an appearance with former Republican congresswoman Liz Cheney during a campaign event on Thursday at Ripon College in Wisconsin. Joel Angel Juarez for The Washington Post

Cheney later asked voters to “reject the depraved cruelty of Donald Trump.”

“Anyone who recklessly tramples on our democratic values as Donald Trump has … must never again stand behind the seal of the president of the United States,” Harris said.

Trump’s campaign responded to the event by highlighting Cheney’s criticism of Harris during the 2020 presidential race. In one August 2020 social media post, Cheney denounced Harris’s “radical leftist views.”

In a Fox News interview before Cheney spoke on Thursday, Trump bashed her as a “stupid war hawk.”

The speech caught the attention of President Biden, who brought it up to reporters unprompted after returning to the White House, according to a White House pool report.

“I don’t know if you got a chance to see but I thought Liz Cheney not only did something that took courage, but physical courage,” Biden said. “It took physical courage. I admire her. Her dad and I worked together a long, long time.”

Harris’s appearance with Cheney marked her fifth trip to Wisconsin, a battleground state, since she started running for president in July – but the location carried added significance. Ripon, which is between Madison and Green Bay, is home to a one-room schoolhouse that has been designated a National Historic Landmark for hosting the first meetings that launched the Republican Party in 1854.

Cheney referenced the party’s founding in Ripon while touting her long history in the GOP, rising to become the No. 3 Republican in the House. She said she cast her first vote in 1984 for Ronald Reagan.

“In other words, I was a Republican even before Trump started spray-tanning,” Cheney said, later adding that she has “never voted for a Democrat” until now.

While Wisconsin is a battleground state, Harris’s trip Thursday took her to a county, Fond du Lac, that is tougher territory for Democrats. Trump defeated Biden there with 63% of the vote in 2020.

A Trump-backed challenger ended Cheney’s reelection bid in Wyoming’s 2022 Republican primary after she became a vocal critic of Trump’s actions in the lead-up to Jan. 6. A former member of House GOP leadership, she voted to impeach Trump over his role in the attack and served as vice chair of the House select committee that investigated it.

Cheney announced she would be voting for Harris during an early September trip to North Carolina, another battleground state. Days later, Cheney’s father – former vice president Dick Cheney – announced he was supporting Harris, too.

Liz Cheney is set to continue campaigning against Trump next week in the battleground state of Pennsylvania. She will join three former Trump White House aides who have since become critical of Trump – Hutchinson, Alyssa Farah Griffin and Sarah Matthews – for a Wednesday event in the Philadelphia suburbs, according to a person familiar with the event, who spoke on the condition of anonymity to discuss details before they were public. CNN first reported the news of the event, which is being organized by a group called Democracy First, and not the Harris campaign.

Trump has sought to counter Harris’s GOP endorsements by winning the support of Robert F. Kennedy Jr., a former independent presidential candidate, and Tulsi Gabbard, a former Democratic congresswoman from Hawaii.

Jan. 6 has been a unifying factor for many of Harris’s GOP supporters, who have otherwise shown sharp differences with Democrats in the past and on other issues in this election. After the Supreme Court overturned Roe v. Wade in 2022, Cheney reiterated on social media that she “has always been strongly pro-life.”

Economic issues also loom large. Hutchinson, announcing her Harris support in a TV interview, sought to appeal to Republicans who are on the fence about supporting Harris but have “very valid concerns about inflation.”

Paul Jeffries, a philosophy professor at Ripon College, said the school has hosted politicians before – including Trump’s vice president, Pence – but Thursday’s event made “for great symbolism.”

“I hope it gives courage to other Republicans across the country to stand up and say, ‘Yes, this is a moment where we need to come together with Democrats and not necessarily see them as oppositional,’” said Jeffries, who supports Harris.

Another Harris backer who came to the event, Penny Byrnes, said she appreciated Cheney’s support for Harris but was unsure how many Republicans it could sway in this day and age.

“It’s great, but how much will she affect stalwart Republicans? I don’t know,” said Byrnes, a 73-year-old retiree from Oshkosh, Wis. “I don’t know much respect they have for her.”

Michael Grenier, a 63-year-old retiree from nearby Berlin, Wis., said Cheney’s support has a “significant” impact on how enthusiastic he is about voting for Harris. Grenier, who said he previously supported Republicans for president, said Cheney represents what he sees as a fading brand of conservatism espoused by Reagan and the late senator John McCain of Arizona.

“She’s all about protecting freedom,” he said of Cheney. “Just knowing that there’s somebody that’s going to carry that lightning rod is a fantastic thing.”

The event coincided with the launch of Wisconsin Republicans for Harris-Walz, which released an open letter Thursday morning backing Harris “to ensure our democracy and our economy remain strong.” The letter has two dozen signees, including three former state legislators.

Harris has promised to appoint a Republican to her Cabinet, raising speculation that a high-profile GOP backer such as Cheney could receive a post. Asked in Austin about possibly serving in a Harris administration, Cheney said she was “not focused on that.”