The Cleveland jails are being emptied and its courts are staying open until 1 a.m. in case of mass arrests. Riot gear, handcuffs, body cameras – police equipment that cost tens of millions of dollars – are ready, and more than 70 law enforcement and government agencies are on alert.

The Republican National Convention opens in Cleveland with a giant welcoming party Sunday in a national political climate so divisive that violence is expected and unprecedented police presence is in place.

“You have a lot of angry people in the United States in 2016, and it seems a lot of it is focused on the political process,” said Ronald Adrine, the presiding Cleveland Municipal Court judge.

Adrine said the Republican convention is the focus of a lot of anger, because “you start with a very controversial presumptive nominee who generates a lot of ill feelings and a lot of support, and those tectonic plates are coming together and going to be moving under Cleveland.”

The close proximity of thousands who love or loathe Trump is what law enforcement is most worried about. The fact that Ohio has an open-carry law, allowing people to walk into crowds carrying a rifle if they have a permit, compounds safety concerns.

‘YOU MIGHT SEE … A BIG GUN’

“We want to be a welcoming presence, but there is a level of anxiety,” said Matt Zone, a Cleveland city council member. He said he and many people in Cleveland are not happy that state laws mean “you might see a sidearm or a big gun,” even though Secret Service have banned water pistols, large backpacks and tennis balls.

No guns will be allowed in the convention center where Trump will speak – nor in the tightest security zone immediately around it.

Zone said the Democratic city has tried to enact gun control laws, but many in the state think that citizens have a right to bear arms, and the state law prevailed. Ohio is evenly divided between Democrats and Republicans, with many supporting the right to carry guns in the open and many opposing it. A new Quinnipiac poll released Wednesday found that Donald Trump and Hillary Clinton are tied in Ohio, each getting 41 percent of the vote.

“I’m not telling people to bring guns, and I’m not telling people to leave their guns at home,” said Tim Selaty, the Houston-based founder of Citizens for Trump. “I’m telling them to come celebrate Mr. Trump’s nomination.”

Selaty said he is encouraging people to livestream themselves during protests for their own security and to cooperate with police as well as private security he has hired. He said everyone is aware that “it doesn’t take much to go from excitement to anger to violence when people try to take that away from you.”

Some members of the New Black Panther Party, a black militant group, have said they plan to bring weapons to Cleveland streets.

Following the recent killing of five police officers in Dallas and the racial tensions raised by a spate of police officers killing black men, there are signs that the crowds could turn out to be smaller than expected.

OFFICIALS: MANY WILL STAY AWAY

City officials said many people who had planned to see the activity surrounding Cleveland’s first political convention in 80 years are now choosing to stay away. Some hotels now have vacancies after last- minute dropouts. And, some protesters are deciding not to come, including some visited recently by the FBI.

“I haven’t seen a permit issued for me,” said Thomas Norton, who had planned a Bikers for Trump parade. He said city officials told him and other organizers that they didn’t need a formal permit to ride their motorcycles. Still, he has decided not to show up since he didn’t get one, “because if something goes wrong they can say, ‘You didn’t have a permit; you weren’t supposed to be there.’ Not doing it.”

Many nationally prominent Black Lives Matter activists said they will skip Cleveland and focus their efforts on the Democratic National Convention in Philadelphia later this month. Several activists said Trump and the Republican Party aren’t going to listen to their concerns, so they have decided it would be a waste of time.

“The RNC is not where this movement is going to converge,” said Mervyn Marcano, an activist who has worked with groups affiliated with Black Lives Matter across the nation. He said local Black Lives Matter activists will be on hand to deliver the message that Trump isn’t welcome, “but most folks in our movement aren’t getting on a plane to waste time with Donald Trump,” he said.