As the DNC began its Monday night programming, anti-Israel demonstrators breached the outer security perimeter, knocking three separate holes in the anti-riot fencing. For about an hour, as they clashed with police, only one more security fence separated the mob from the site of a major party’s national convention. Were it not for the resolution and preparedness of the Chicago police, the dicey situation may have spiraled out of control.

America’s popular system of government has always faced threats from the anti-democratic, anti-American forces of tyranny. (Though it’s less common for sitting presidents to concede at their party’s convention, as Biden did Monday, “Those protesters out in the street, they have a point.”)

A coalition of more than 100 left-wing groups have planned at least seven protests against the DNC, consciously fostering parallels to the 1968 Democratic National Convention in Chicago, where demonstrators clashed with police over the Vietnam War. But “grassroots” protesting has become a big business, and left-wing groups laid out hundreds of signs at Union Park, waiting for protestors when they arrived.

Now, their anger is directed against the Biden-Harris administration. Despite the administration’s constant capitulations, these pro-Hamas agitators believe the U.S. government isn’t backstabbing Israel hard enough, and they refuse to be satisfied as long as the Biden-Harris administration permits the world’s only Jewish nation to exist. In addition to the mass-produced signage, protest organizers assembled giant, paper mâché effigies of “Killer Kamala” and “Genocide Joe,” like the effigy of Israeli Prime Minister Benjamin Netanyahu burned last month in Washington, D.C.

Rallygoers waved Palestinian flags and green smoke flares, with shouting that could be heard two blocks away from the main entrance to the United Center, home to the Chicago Bulls and Blackhawks, where the DNC is taking place. At around 5:00 p.m., a group broke away from the main protest route at Park #578 (a neighborhood park where the main feature is a playground), four blocks west of Union Park.

This splinter group then began to assail the security fence surrounding the DNC, which was installed along Washington Boulevard. At first, they tried shaking the fence apart, a tactic pro-Hamas protestors employed on a security fence around the White House in January. But this proved ineffectual, as the fence was anchored with a concrete barrier, and after about 20 minutes the crowd mostly just stood there screaming.

But then one of the agitators decided to try a new tactic — working smarter, not harder. With an application of force to the joint connecting adjacent fence panels, he lifted up a fence panel and threw it out of the line, much like taking some doors off their hinges. (With the frequent opportunities D.C. affords for viewing anti-riot fencing up close and at leisure, I’ve been wondering for four years when the leftists would figure out this trick.) Minutes later, the agitators dislodged a second fence panel, followed by a third.

Interestingly, it seems the activists had no real plan. (Imagine what could have happened if they had!) After breaking through the fence at around 5:30 p.m., the mob dithered around for five minutes debating whether to enter. A handful of officers stationed nearby held the crowd off for a while but were eventually overrun. These factors gave the police valuable minutes to scramble vans full of officers in response, but the crowd had already poured into the street when reinforcements arrived.

Fortunately, someone in charge of security had the foresight to erect a second security fence. Still, only one remaining fence separated the pro-Hamas demonstration from the parking lots that surrounded the convention site. And the crowd that had so effectively dismantled the first fence was assailing the second fence also.

By around 6:00 p.m., the Chicago police had assembled in force. Lines of officers in protective gear steadily pushed the crowd back, as the “mostly peaceful” demonstrators threw their mass-produced signs, bottles, and other objects at the officers. The police arrested at least four people in the scuffle; at least one arrest involved a struggle.

The police soon recovered the fence’s outer perimeter, but their hazardous duty was not over yet. The pro-Hamas mob had simply retreated to the safety of the playground, where they could not be allowed to remain. Hundreds more police arrived by 6:30 p.m. to surround Park #578 on three sides. Some police began “clashing with rioters en route to [W] Maypole [Ave] & [N] Wolcott [Ave],” the intersection on the park’s northeast corner. The police assembled in forceful lines and slowly, steadily pushed the activists out of the park. By 6:54 p.m., the park was cleared.

Even then, the pro-Hamas column continued creating mischief. Shortly before 8:00 p.m., demonstrators erected a pop-up encampment in Union Park, evoking those erected on college campuses this spring. Activists spray-painted “Pig-Free Zone” in the park and set up tents. “Cops walked straight for tents but now are stopped as protestors surround them,” a Mother Jones reporter tweeted. However, the Chicago police soon assembled in force and displayed posters ordering the crowd to disperse. “Rather than face arrests or violence, the activists took down their tents and mostly dispersed,” another reporter said. The park was clear before 9:00 p.m.

Throughout the first and second days of protests at the DNC, Chicago police distinguished themselves by quickly shutting down any sort of disorder and arresting those responsible (whether they stay in jail under Illinois’s cash-free bail system is another question). They mostly did this by showing up in force — hundreds of well-equipped officers responding as needed to various incidents.

Of course, the week is just getting started, and protestors have already shown the ability to innovate their tactics — and dismantle the anti-riot fence. For a group that glorifies the “Battle of Michigan Ave” in 1968, they’ll likely try to do better than the “Battle of the Playground” or the “Battle of Park #578.” Monday’s misdeeds could simply have been the mob testing the waters. More disorder could lie ahead.

However, so far, Chicago has demonstrated that it is possible to contain radical left-wing protestors and that letting them have free reign to destroy a city and its parks is a choice. As Illinois Governor J.B. Pritzker (D) declared, “We’re not going to stand for any mayhem.” This is what all cities should aim for at all times, not just when the Democratic National Convention is in town.