Standing in a packed amphitheater in front of Mount Rushmore for an Independence Day celebration, President Trump on Friday delivered a dark and divisive speech that cast his struggling effort to win a second term as a battle against a new far-left fascism seeking to wipe out the nations values and history. With the coronavirus pandemic raging and his campaign faltering in the polls, his appearance amounted to a fiery reboot of his re-election effort, using the holiday and an official presidential address to mount a full-on culture war against a straw-man version of the left that he portrayed as inciting mayhem and moving the country toward totalitarianism. Our nation is witnessing a merciless campaign to wipe out our history, defame our heroes, erase our values and indoctrinate our children, Mr. Tump said, addressing a packed crowd of sign-waving supporters, few of whom wore masks. Angry mobs are trying to tear down statues of our founders, deface our most sacred memorials and unleash a wave of violent crime in our cities. Mr. Trump barely mentioned the pandemic, even as the country surpassed 53,000 new cases of the coronavirus and health officials across the country urged Americans to scale back their Fourth of July plans as the pandemic made a frightening resurgence. Instead, the president leaned into the culture wars that invigorate his base of supporters. Railing against what he described as a dangerous cancel culture, Mr. Trump said the left wanted to unleash a wave of violent crime in cities across the country. He said they think the American people are weak and soft and submissive. In contrast, he framed himself as the leader who would protect the Second Amendment, law enforcement and the countrys heritage. His speech came at the end of a day when at least five states Alabama, Alaska, Kansas, North Carolina and South Carolina reported their highest single day of cases yet. Newly reported cases of the virus were rising in all but a handful of states, and many large cities, including Houston, Dallas, Jacksonville and Los Angeles, were seeing alarming growth. Mr. Trump planned to follow up his trip with a Salute to America celebration on Saturday on the South Lawn at the White House, marked by a military flyover and the launch of 10,000 fireworks on the National Mall. Mayor Muriel E. Bowser of Washington has warned the gathering violates federal health guidelines. The Trump administration, which controls the federal property of the National Mall, pushed for the celebration, ignoring a mayor officials view as a political rival. Throughout his presidency, Mr. Trump has tried to bend events to his will, often using social media to drive home his alternate version of reality and, thanks to the power of repetition and the loyal support of his base, sometimes succeeding. But the presidents attempt to drive deeper into the culture wars around a national holiday, during an intensifying health crisis that will not yield to his tactics, risked coming across as out of sync with the concerned mood of the country at a moment when his re-election campaign is struggling and unfocused. I dont think it will work, because what he is trying to do is pretend that the situation is better than it is, said Michael Beschloss, the historian and author of Presidents of War. Mr. Beschloss compared Mr. Trump to Woodrow Wilson, who presided over the influenza pandemic in 1918 by trying to pretend it was not happening, and to Herbert Hoover, who in 1932 tried to project that the Great Depression was not as bad as people were saying. People voted him out because they felt he did not understand the suffering, Mr. Beschloss said, referring to Hoover. Mr. Beschloss said that while presidents had always celebrated the Fourth of July, it was also highly unusual to turn it into a partisan rally. Most presidents in history have understood that when they appear at a national monument, its usually a moment to act as a unifying chief of state, not a partisan divider, Mr. Beschloss said. Mr. Trump has consistently played down the concerns over spikes in new cases, even as many cities and states have had to slow or reverse their reopenings, claiming that young people get better much easier and faster, that the death rate is declining and that the virus will just disappear. On Thursday, he lauded his administrations response, referred to the surge in new cases as temporary hot spots and focused instead on what he said was evidence of the economy bouncing back. A lot of people would have wilted, Mr. Trump said at a news conference where he praised the latest job numbers. We didnt wilt. Our country didnt wilt.