Many critics of Donald Trump consider the rally cancellation in Chicago a victory, but the candidate’s divisive rhetoric and seeming encouragement of violence against protesters could spiral out of control in the months ahead. Photograph by Jabin Botsford / The Washington Post via Getty

For the past eight months, Donald Trump’s divisive, racially tinged Presidential campaign has been tearing apart the Republican Party. Over the next eight months, if Trump wraps up the G.O.P. nomination, it could well have a similar impact on the country at large.

The fracas at a University of Illinois at Chicago campus on Friday, in which hundreds of protesters clashed with Trump supporters live on national television, shocked many people. But something like this was inevitable once Trump took his rabble-rousing campaign from predominantly white suburbs and exurbs to polyglot Northern cities, which are home to many of the people, including Hispanics and Muslims, who serve as the objects of Trump’s rhetoric, as well as to an energetic left-wing protest movement.

The effort to shut down Trump’s rally was prompted by anger that the New York billionaire would seek to bring his campaign to the college, which has a very diverse student body. As Alex Seitz-Wald detailed in a report for NBC News, a number of student organizations decided at a meeting last Monday to organize a protest. “He’s marginalized and dehumanized a lot of different groups, and they all come together,” Juan Rosas, one of the student organizers, told Seitz-Wald. After a student posted a petition on MoveOn.org, outside groups and activists also got involved. “Everyone, get your tickets to this. We’re all going in!!!! ‪#‎SHUTITDOWN,” Ja'Mal Green, a Chicago activist and singer who has been helping to organize protests against the city’s mayor, Rahm Emanuel, wrote on his Facebook page.

From the point of view of the protest’s organizers, Trump’s decision to call off the rally was a great success. And it is likely to encourage similar efforts in other cities. “Remember the #TrumpRally wasn’t just luck,” People for Bernie, a group of activists that supports Bernie Sanders’s Presidential campaign (but isn’t formally associated with it), tweeted shortly after the Chicago event was cancelled. “It took organizers from dozens of organizations and thousands of people to pull off. Great work.”

Some parts of the Democratic Party and its media environs raised concerns that the protesters had played into Trump’s hands by denying him and his supporters their rights under the First Amendment. Trump himself was quick to make this argument. “Whatever happened to freedom of speech?” he asked during an interview with MSNBC’s Chris Matthews. “Whatever happened to the right to get together?”

It is worth recalling, of course, that Trump himself has for months been calling for protesters at his rallies to be silenced—and has even, on occasion, appeared to be inciting violence against them. In a post on Friday, Vox’s Dara Lind compiled some of Trump’s incendiary statements, including this one, which he made on February 1st, in Cedar Rapids, Iowa: “If you see somebody getting ready to throw a tomato, knock the crap out of ’em, would you? Seriously. Okay? Just knock the hell—I promise you, I will pay for the legal fees. I promise. I promise.”

As concerns about the violence at his rallies have grown, Trump has consistently denied responsibility. But he has also continued to say inflammatory things. When he appeared in St. Louis on Friday, just hours before his planned appearance in Chicago, police removed a number of people who tried to interrupt him. According to a report in Saturday’s Daily News, as the police slowly escorted out one individual, the crowd chanted “U.S.A.! U.S.A.!,” and Trump told them, “Part of the problem, and part of the reason it takes so long [to remove demonstrators] is nobody wants to hurt each other anymore. . . . And honestly, protesters are realizing that there are no consequences to protesting anymore. There used to be consequences. There are none anymore.”

So, where do we go from here?

It isn’t every day that a self-promoting huckster with an authoritarian streak—one who has endorsed torture, accused American Muslims of cheering 9/11, and called undocumented Mexican immigrants “criminals, drug dealers, rapists”—stands on the verge of becoming the Presidential candidate of a major political party. To many members of minority groups, the sight of Trump and Trumpism atop a national ticket would represent a grievous insult to their dignity, and a potential threat to their well-being; to many moderates, liberals, and leftists of all backgrounds, it would represent a moral outrage. The anti-Trump forces won’t stand back and let him parade around the country unopposed. They will exercise their democratic right to protest against him and what he represents, and some of them will be disruptive. Which, doubtless, will provoke more anger from Trump and his supporters.

After watching some of the footage from Chicago on Friday night, I commented on Twitter, “Chicago protest: Newton’s Third Law is starting to kick in—for each action, there is an equal and opposite reaction. Only the beginning.” In response, Paul Staniland, an assistant professor of political science at the University of Chicago, who co-founded the school’s program on political violence, wrote, “I spend too much time studying violence not to get a pit in my stomach thinking about how this all could spiral.”