There was a palpable sense of unease in Milwaukee on Sunday, on the eve of the Republican National Convention. The event was already sure to be a chaotic chapter in our ugly national political drama. But the drama suddenly got even grimmer this week, when Donald Trump, who will eventually accept the GOP nomination here, narrowly survived an assassination attempt at a Pennsylvania rally the day before.

To some extent, business has still been going on as usual: Journalists are descending on the city; party officials are convening; and supporters of the former president are giddily strutting around in MAGA swag. But the mood has unmistakably shifted: Trump supporters held a prayer vigil for him in a park near the Fiserv Center, home of the Milwaukee Bucks; and the Daily Show, which had been slated to broadcast here all week, canceled its on-the-ground programming. After all, who was in a joking mood?

On Sunday, law enforcement officials stood around the convention’s perimeter, sweating and talking about the humidity. The event grounds were so empty you could hear the squawk of gulls over Lake Michigan. At a bar nearby, politicos gabbed over glasses of pinot noir and old-fashioneds. “Trump’s speech is going to be epic,” one predicted. “I feel like we’re living in the 1960s right now,” another said.

“To America,” they toasted.

Up until Saturday, questions surrounding the viability of President Joe Biden’s reelection bid—as well as Trump’s vice-presidential pick and extreme right-wing agenda for a second term—were likely to be the main topics of discussion at the RNC. However, much of this is now likely to be overshadowed by the attempt on Trump’s life. Biden condemned the shooting—which claimed the life of one at the rally and wounded two others—and offered his thoughts to Trump. “There is no place in America for this kind of violence,” the president said. “Unity is the most elusive goal of all. But nothing is as important as that right now.”

Trump, meanwhile, flew into Milwaukee Sunday, undeterred. “I cannot allow a ‘shooter,’ or potential assassin, to force change to scheduling, or anything else,” he wrote online, as the political world turned its attention to this city of 500,000, situated in a key swing state that helped decide the election for Trump in 2016 and Biden in 2020.

On the night before this year’s Republican convention, America remains a deeply troubled nation—culturally and politically polarized, its democracy teetering and its center struggling to hold. This week in Milwaukee is set to be sweltering; as for the country, the temperature is already at a boiling point.