They turned the volume up to 11 on Monday. The protesters, partisans and rabble-rousers arrived in full force, their movements shadowed by scores of police officers.
Donald Trump supporters, some affiliated with far-right organizations that have a dim view of the Republican establishment, held a rally by the Cuyahoga River, chanting "Hillary for prison!" and lambasting "globalists," the elite media, and GOP operatives determined to deny Trump the nomination.
Equally passionate Trump protesters marched through the streets demanding an end to police brutality and anti-immigrant policies, and chanting "Dump Trump!" and "Hey hey! Ho ho! Donald Trump has got to go!"
They two groups were only a few blocks apart but never crossed paths. Nor was such an encounter likely given the extraordinary police presence, many from as far away as California and Florida. The Cleveland police chief has said there are "thousands" of police from "hundreds" of departments on hand.
Local officials and political observers have been concerned about clashes between the pro- and anti-Trump factions, a scenario made more ominous by Ohio's "open carry" law permitting citizens to carry loaded handguns and rifles.
"If there's gunfire that erupts, the guys that are armed, they're probably going to fire back," predicted Pete Bryan, 49, a Dayton, Ohio, auto dealership employee who was part of a Bikers for Trump contingent at the river rally.
But as the gavel dropped on the Republican National Convention on Monday, the scene on the streets continued to reflect the First Amendment rather than the Second. The city is not full of ordinary citizens walking around with assault rifles strapped to their backs. So far.
The Trump rally was organized by controversial former Trump adviser Roger Stone, and promoted by Alex Jones, proprietor of the conspiracy-slinging website infowars.com. A series of speakers invoked Trump's theme of making America great again, and one woman told the story of how her son was tortured and murdered by an illegal immigrant.
Then Jones, wearing a blue blazer that clashed with the biker garb around him, took the stage. The crowd surged forward. Jones spoke in tones ranging from loud to roaring. His rhetoric became so hot he threatened to catch the Cuyahoga on fire.
"This planet and the globalists have not seen anything yet!" he bellowed.
He said authorities had imposed a no-fly zone around Cleveland, which explained the absence of the airplane that had been pulling a "Hillary for Prison" banner over the weekend.
"They're afraid of free speech," he said. "These are anti-free-speech, anti-freedom scum who need to get their a-- to North Korea!"
He called Hillary a foreign agent of the communist Chinese and Saudi Arabians, and went on to lionize Trump: "Everything he's been doing has simply been absolutely over-the-top amazing."
Less than a mile away, hundreds of Trump protesters gathered in Cleveland's Veterans Memorial Park, many with banners and placards condemning the presumptive GOP nominee. Some had walked all the way to Cleveland from Chicago. But many organizations on the political left have decided to skip the Republican convention, seeing little to gain from the gathering, and focus instead on the Democratic convention, where protests might conceivably have more influence.
"This isn't a rally of the biggest names in the world, but there are real activists here with real struggles," Mick Kelly, a member of the Coalition to Stop Trump and March on the RNC, told the crowd, which including groups opposing corporations and capitalism and supporting gay and lesbian rights and immigrant rights.
Clutching a sign demanding that Trump read the Constitution, Faten Odeh, a social sciences teacher and a Muslim who lives in Cleveland, said she had come out to oppose the divisive rhetoric of the Trump campaign.
"Our Constitution says that all men are created equal, and that all people have the right to life, love and the pursuit of happiness no matter what," she said. "It doesn't specify that you have to be white, it doesn't specify that you have to be Christian."
After a series of speeches, the protesters began a raucous but fundamentally orderly march through the streets, passing within a few blocks of the Trump rally, and then directly by the Quicken Loans Arena, where Trump is scheduled to accept the GOP nomination Thursday night. The march followed a planned route, with many people in red or black T-shirts and carrying banners.
"We're here to show that these streets are ours, too. No Trump supporter, no policeman can shut us down," shouted one protester, his face covered by a thick scarf as the midday sun beat overhead.
The march appeared to have at least 1,000 participants, though any crowd estimate was complicated by the heavy presence of news media, Amnesty International observers, lawyers poised to offer legal help for protesters facing charges, peacekeepers, journalists, self-directed videographers, and presumably a large number of undercover law enforcement officers.
The marchers made it back to their starting point without a hitch. Tensions rose moments later when a group of religious extremists appeared, timing their arrival with the end of the march. Police used their bikes to separate the two sides, standing their ground as the group identifying itself as "Bible Believers" screamed homophobic slurs through megaphones and excoriated the Black Lives Matter protesters.
Both sides sloped away quietly in the end, thronged by many of the 15,000 journalists who have descended on Cleveland.
The police have been low key so far, staying back, and essentially escorting protesters through a city lined with barricades, fences and barriers. Police Chief Calvin Williams said Monday that a modest-sized protest Sunday had culminated in a single arrest. A protester, whom he described as possibly having mental problems, grabbed a gas mask from a police officer and was charged with petty theft.
Williams himself spent three hours Sunday night riding around his city on a new $2,000, Safariland bicycle made expressly for law enforcement, one of 300 bikes purchased for crowd control in advance of the convention.
He said his officers are keenly aware of the killings of police officers in Dallas and Baton Rouge. After Dallas, he said, he ordered his officers to ride in pairs and not to patrol alone.
He said he made sure Sunday that his commanders learned about what happened in Baton Rouge, but he did not indicate any changes in tactics. After the news conference, he said he doesn't personally worry about being targeted.
"If you worried about that, I'd be going like this all day long," he said, turning his head side to side as if scouting enemies. "I don't walk around thinking somebody's going to snipe me. I don't do that. You can't function like that."