So, this happened in Chicago tonight:

Donald Trump has canceled his rally at the UIC Pavilion due to safety concerns. A speaker came out to the podium and made an announcement. “Mr. Trump just arrived in Chicago and after meeting with law enforcement has determined that for the safety of all the tens of thousands of people that have gathered in and around the arena, tonight’s rally will be postponed until another date. Thank you very much for you attendance and please go in peace,” he said.

More:

As many as 10,000 people had tickets to attend the rally and at least 7,000 were in the Pavilion at the time of the cancelation. The line still stretched several blocks around the building. A crowd of protesters outside the area swelled to at least 1,000 people. Protesters outside the Pavilion were loud, but peaceful. Inside the Pavilion, there appeared to be thousands of protesters in attendance, mostly young people and UIC students. Upon the announcement of the cancellation, they began shouting “We stopped Trump! We stopped Trump!”

And:

“It was quite disappointing that they couldn’t cancel because we feel it’s not just offensive to us, the things that he’s spreading, but it’s also something- we feel unsafe here on campus having someone like that here, and his supporters,” says Asa Wahdan, of the UIC Muslim Student Association.

Get this:

Many attendees came from Indiana and Wisconsin, making it a day trip to see the candidate they support. They were disappointed it was canceled.

From the Washington Post‘s account:

Protesters and supporters of Donald Trump clashed in sometimes-violent fashion here and in Chicago on Friday, the latest in an escalating series of confrontations that have come to define the front-runner’s rowdy campaign rallies even as he gets closer to securing the Republican nomination. In the evening in Chicago, Trump canceled a rally at the University of Illinois at Chicago after brawls broke out at the event site.

More:

Inside the Peabody Opera House in St. Louis earlier in the day, protesters interrupted Trump eight times, prompting catcalls and chants from the crowd as security officers removed them. Scores were injured or arrested in clashes between Trump supporters and critics outside the venue, where thousands had gathered in an overflow area to listen to the event over loudspeakers.

And:

“God! Why do you create fools?” an exasperated Trump supporter said, as he watched a young Latino man yelling at a small group of Trump supporters and flashing his middle fingers.

One more:

The crowd was notified by a loud announcement that the rally had been postponed. The protesters immediately erupted into cheers and chants of “We stopped Trump,” while many Trump supporters stood stunned, many having waited hours to see the candidate. Soon, shoving matches broke out between the two groups, and police tried to break up one scuffle after another. Everyone moved outside, and the crowd grew in numbers and the altercations continued. Five people were arrested, a Chicago police spokesman said. “You can’t even have a rally in a major city in this country anymore without violence or potential violence,” Trump said in an interview on MSNBC. “I didn’t want to see the real violence, and that’s why I decided to call it off.”

Earlier in the day, at a Trump rally in St. Louis:

Less than 10 minutes after Trump took the stage, as he was in the midst of a complaint about how the media does not portray his rallies as “love-fests,” protestors sprang up from all corners of the room. Holding court at his podium and flailing his arms, Trump yelled directives as police officers gingerly tried to remove Black Lives Matters protestors. One group disrupted Trump’s speech for nearly 15 minutes, spanning two rows and intertwining their arms to create an impenetrable circle, yelling “STOP THE HATE” and waving signs that read “NOT YOUR LAZY BLACK.” The corridors of City Hall were a picture of mayhem.

Yesterday I wrote denouncing the air of thuggery around Trump rallies, in particular the old coot in Fayetteville who punched an anti-Trump demonstrator. I stand by that opinion. We cannot have a democracy if people are going to get physically assaulted at a political demonstration. That loudmouth protester was in the process of being removed from the building when that jerk old man sucker-punched him. He was arrested, the old man, and charged. I hope he pays a legal price for that behavior. We cannot have that.

Getting the Chicago news, though, gives me a strongly pro-Trump feeling. These left-wing demonstrators tried to shut down an American presidential candidate’s speech during the campaign — and they succeeded, through an implicit threat of violence. People who support Trump drove hours to hear him talk, and they were denied their constitutional rights by left-wing hotheads who believe that they are so righteous that they don’t have to observe basic civility. You come to a Trump rally and you start flipping people off? You should not be surprised if you get a sock in the face.

What happened tonight in Chicago is why we need Trump, as obnoxious as he is, to keep going. I am not a Trump supporter, and I reject much of his rhetoric. But he has a right to give a speech, even an obnoxious speech, without it being interrupted by demonstrators. All of us do. Trump is revealing how impossible it is to have a normal democracy with the activist left, who think their crying need for “safe spaces” gives them the right to silence their opponents.

No. This political correctness needs to be opposed, and it needs to be opposed with force. I don’t know why the police couldn’t handle this situation, but they had better be on it in the future, because many Americans will not stand for this. What those protesters have done tonight is create a lot more Trump voters out of people who are sick and tired of privileged leftists using thug tactics to silence their opponents.

I would feel exactly the same way if conservative protesters tried to shut down a Hillary Clinton or Bernie Sanders rally. Protest all you want, but do it outside the venue, or silently inside. Do not silence the speaker, because if you do that, you legitimize your opponents trying to silence the speakers from your side. Thuggish, illiberal tactics like this from the left call forth the same kind of thing from the right. When right-wing white nationalist types show up and make trouble at Democratic rallies, or BLM rallies, and get them cancelled, on what grounds will you on the left have to complain?

For me, it’s all about the mob. I despise the mob. Any mob, which I define as a crowd that acts in force to silence people by intimidation or actual violence. We have seen over the past few months how left-wing mobs on college campuses have gotten away with outrageous things, because men and women in authority on those campuses lacked the guts to stand up for the liberal civic order. This is why I cannot support Black Lives Matter, even though I support its goal of bringing critical attention to police brutality: because they believe that their cause is so righteous that they have the right to stomp over anybody who doesn’t share their vision.

Don’t y’all understand that people like you only feed the Trump beast?

Unlike the liberal New York Daily News — and, no doubt, the rest of the mainstream media — I do not blame Donald Trump for this tonight. I blame the left. You want to protest against Trump? Great — that’s your right as an American. But you do so silently and peaceably. You let the man speak. It’s his right as an American, and it’s the right of the people in the audience to hear his message, however offensive it may be to you, and make up their mind about it.

This has gone too far. When an American presidential candidate has to cancel his rally in a major city because protesters have made it too dangerous, we have a serious problem in this country. It’s infuriating. This is not America. Those disruptive protesters need to be made to understand that this is not how America works.

Keep at it, Black Lives Matter and fellow travelers. You are going to get Trump elected.

UPDATE: A reader writes:

I just finished a conversation with a dear friend about how I am voting for Bernie because I believe the best thing for poor communities -white and black communities alike – is the availability of good blue collar work. He shot back that I was a racist for privileging economics over things like police violence and institutional racism. This is what makes Trump supporters out of people like me. (I am voting for Bernie in the primary after that, I have no idea…) The contempt of the Left for people who disagree – even people like me who vote Democratic and stand with them on most (not all) issues! I don’t know what to do anymore. Mostly I’ve decided to keep my mouth shut in the company of my liberal friends lest I be revealed as an enemy of the Revolution.

Good job, Social Justice Warriors. Trump ought to pay you for what you do.

UPDATE.2:Tim Stanley, in the Telegraph (H/T Devinicus):

Trump is a blowhard. His views are unconstitutional, illiberal and sometimes they trigger hate. But he did not take America to war in Iraq on flimsy evidence, establish Guantanamo in contravention of human rights law, licence the torture of enemy combatants, oversee the gargantuan NSA data-gathering operation, launch a dirty war of drone strikes against both terrorists and those unfortunate enough to live near them, undermine the religious freedoms of employers who do not want to subsidise the sex lives of their workers, overrule the states’ wishes on marriage, compel citizens to buy healthcare products or deport thousands of illegals through aggressive round-ups. No: these things were done by “moderate” Republicans and “liberal” Democrats. Trump is not new. The violence in Chicago has been a part of American politics for a very long time. The angry nihilism of the far-Right has incubated for decades; the “no platform” tendency of the Left is authoritarianism by any other name. And the slow corruption of American republicanism – the growth of the state and the willingness of politicians to do anything to get votes – began long before The Donald threw his hair into the ring. Trump is not a political crisis in isolation but, rather, a symptom of wider institutional failure. A symptom of American political decline.

(“No platform” is Britspeak for the movement in the UK to deny right-of-center speakers the right to speak, usually at universities.)

I have been saying for some time that Trump is a symptom, and of course Stanley nails what, excatly, he’s a symptom of: American decline. I wonder what, exactly, the SJWs expect? That everybody in America will behave as college administrators, and give in to whatever their sacred selves demand? I believe that behind her boilerplate Establishmentarian rhetoric, Hillary Clinton will do her best to protect a system that allows for the dismemberment of babies in the womb and trade in their body parts. I believe she, like all other national Democrats, and their allies will stop at nothing to restrict the religious liberty of orthodox Christians, and impose legal penalties on us for practicing our faith in a way that conflicts with progressive orthodoxy. I believe that there is nothing that the SJWs demand that she would not try to accommodate as president, no matter what cost it put on people like me. I think she is a serious threat to people like me, aside from the fact that she supports the dismemberment of unborn children, though euphemizes it in politically neutral rhetoric.

For all that, if social and religious conservatives started showing up at Clinton rallies with the intention of disrupting them so the candidate could not speak, and her supporters could not hear her speak, I would be appalled. We see this on the right, when pro-life extremists harass abortion doctors in their homes. I think abortion doctors are wicked, but certain lines must be respected if we are not going to fly apart as a society. The right of people to be at peace in their homes is a fundamental right. I would also say this is true of the right of people — even bad people — to speak their minds at their own events.

When a gay mob in San Francisco about 10 years back physically drove a small group of Evangelical Christians out of the Castro, it was disgusting and frightening. When I wrote about it, lots of people responded saying that they deserved it, going into a gay neighborhood and preaching against the wickedness of homosexuality. As I said then, it was a foolish thing to have done, but here’s the thing: it’s as legal in this country to do as the Klan marching through Skokie was. And it is important not only to observe the First Amendment by the letter of the law, but also to cultivate its spirit.

We have watched over and over in this country SJWs shut down speech they don’t like, and win meaningful concessions from college administrators as a reward for their obnoxious activism. Again: Trump is a demagogue who enjoys baiting the SJWs. I think he’s irresponsible at best. But what he reveals are deep divisions that are already present in our politics, and he fights back — in a crude, even dangerous manner — in ways that none of the Republican elites do. It is strange that the SJWs have been able to act in illiberal, rhetorically violent, even physically aggressive, ways for some time in this country, and nothing much happens to them. Trump’s people do it, and suddenly it’s the end of the Republic.

It may be the end of the Republic, and Trump has his role in bringing it about. But he didn’t start it. For what that’s worth.