At the foot of Mount Rushmore’s granite monument to his presidential forebears, President Trump on Friday delivered a dark speech ahead of Independence Day in which he sought to exploit the nation’s racial and social divisions and rally supporters around a law-and-order message that has become a cornerstone of his reelection campaign.

Trump focused most of his address before a crowd of several thousand in South Dakota on what he described as a grave threat to the nation from liberals and angry mobs — a “left-wing cultural revolution” that aims to rewrite U.S. history and erase its heritage amid the racial justice protests that have roiled cities for weeks.

Praising presidents George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt, the men carved into the cliffs behind him, Trump declared that their legacies are under assault from protesters who have defaced and torn down statues. As he has done with increasing fervor in recent weeks, the 45th president denounced not just rioters and vandals but also much of the social movement that propelled the mass demonstrations in response to the killings of black men at the hands of police.

“The radical ideology attacking our country advances under the banner of social justice. But in truth, it would demolish both justice and society,” Trump said. “It would transform justice into an instrument of division and vengeance and turn our free society into a place of repression, domination and exclusion. They want to silence us, but we will not be silenced.”

The president, who recently signed an executive order aimed at punishing those who destroy monuments on federal property, referred to “violent mayhem” in the streets, even though many of the mass demonstrations have been largely peaceful. He warned that “angry mobs” were unleashing “a wave of violent crime” and using “cancel culture” as a weapon to intimidate and dominate political opponents — in what he compared to “totalitarianism.”

And Trump asserted that “children are taught in school to hate their own country and to believe the men and women who built it were not heroes but villains.”

“This radical view of American history is a web of lies,” he added.

“They think the American people are weak and soft and submissive,” Trump said. “But no, the American people are strong and proud, and they will not allow our country and all of its values, history and culture to be taken from them.”

His address was capped by a fireworks display above the federal monument in what White House officials have touted as a weekend of celebrations around Independence Day that will continue with the president presiding over another fireworks event in Washington on Saturday.

Though the Mount Rushmore trip was billed as an official White House event, the president made an overt appeal to his partisan supporters in attacking liberals. His appeal came as he has faced tumbling public approval over his handling of the mass protests and the deadly coronavirus pandemic.

Yet Trump’s efforts to rejuvenate his struggling reelection campaign with events in front of large crowds outside Washington was set back for a second time after Kimberly Guilfoyle, a Trump campaign fundraiser who is dating his son Donald Trump Jr., tested positive for covid-19, the disease caused by the coronavirus, ahead of the president’s arrival in South Dakota.

Guilfoyle had not arrived at the venue and was not in contact with Trump, and Don Jr. has tested negative, said a person familiar with the situation who spoke on the condition of anonymity to discuss their personal situation. A campaign aide said Guilfoyle was asymptomatic, but she and Don Jr. were both isolated from others and intend to cancel upcoming public events.

The two are planning to drive back to Washington to avoid contact with others, said the person who spoke on the condition of anonymity. The New York Times first reported Guilfoyle’s positive test Friday evening.

In his remarks, Trump, whose son Eric and daughter Tiffany were in attendance, did not mention Guilfoyle and he largely avoided any mention of the coronavirus, other than thanking doctors and first-responders for their efforts to contain the outbreaks.

Guilfoyle’s diagnosis came two weeks after Trump’s campaign rally in Tulsa — the first after a months-long hiatus amid widespread coronavirus shutdowns — was marred when several campaign staffers and Secret Service agents contracted covid-19.

Trump has sought to minimize the threat from the pandemic as he pushes for much of the nation to reopen businesses, touting this week a better-than-expected jobs report from mid-June. Yet experts have warned that spikes in the coronavirus in many states, which have contributed to new cases in the United States topping a record 50,000 per day this week, are likely to dampen the economic recovery.

Trump, who has faced criticism from lawmakers in both parties for his refusal to wear a mask in public and reluctance to encourage Americans to do so, maintains that the surge of new cases is a result of increased testing capacity and that the virus will soon “disappear.”

Trump arrived in South Dakota just as sheriffs and the National Guard cleared dozens of demonstrators blocking a key artery leading to the site.

The mostly Native American demonstrators, protesting the taking of land from the Lakota people, gathered hours before Air Force One arrived in the state. They chanted, held signs and sang songs as members of the National Guard and local authorities dispersed the crowd using pepper spray, according to the Associated Press. Police also towed three vans that blocked the road.

The tribes had warned that Trump’s push for fireworks, which have been banned at the site for more than a decade, could result in wildfires and contaminate the water in the surrounding Black Hills. And they have voiced serious concern that a massive gathering without any safety restrictions could cause a coronavirus outbreak in their communities.

Ahead of Trump’s visit to the monument, the Mississippi flag was removed from an area of the site where all 50 states’ and U.S. territories’ flags fly. Mississippi’s legislature voted this week to remove the Confederate symbol from its flag and thus the state’s flagpole will be empty.

In his speech, Trump vowed that Mount Rushmore “will never be desecrated. These heroes will never be disgraced. Their legacy will never, ever be destroyed. Their achievements will never be forgotten. And this monument will stand forever as an eternal tribute to our forefathers and our freedom.”

The crowd stood and applauded, while chanting, “USA! USA!”