In Wisconsin, a group of environmentalists plans to bicycle to Chicago's G-8 and NATO summits to protest an economy that relies too heavily on fossil fuel.
In California, a nurses union has a permit for a Chicago march the day before the summits to highlight economic inequalities and a lack of health care for too many Americans.
Near and far, similar groups are scheduling their own trips to Chicago for the May 19-21 financial and security meetings here to protest the policies of the world's most powerful leaders. Crowd estimates range from an early Chicago Police Department estimate of 2,000 to 10,000 demonstrators to the national Occupy movement's call for 50,000.
"It's obviously the $64,000 question — I've seen estimates of thousands of protesters and tens of thousands. No one really has any idea," said Jeffrey Cramer, head of the Chicago office of Kroll, a corporate security firm doing work related to the summits.
That leaves city officials, Chicago police, federal agencies and security experts who advise corporations all trying to figure out who will show up and whether anybody will be looking to cause trouble.
A reminder of the stakes came Thursday in federal court, where city lawyers agreed to pay $6.2 million to about 800 people detained by police in what a judge called unjustified mass arrests that ended a 2003 Iraq War protest downtown.
Mayor Rahm Emanuel and event organizers are playing down the potential for violent protest and focusing on the chance to showcase Chicago as an international tourism and business center. The rare back-to-back meetings of the Group of Eight industrialized nations and the NATO gathering of key U.S. military allies in one city will bring worldwide attention.
At the same time, authorities are drawing up contingency plans for possibilities that range from downtown streets choked with demonstrators to elusive bands of anarchists who could show up to tangle with police.
"It's apprehension of the unknown," Cramer said.
Many protest group leaders say they are committed to causing no harm, but they acknowledge they are likely to see multiple sources of conflict with police while they're here. From anonymous provocations of violence on the Internet to troublemakers mixed in with the protesters, when anxious cops and simple breakdowns in crowd control mix, a lot could go wrong.
One of the 2003 anti-war protesters in line for the city settlement, Cheryl Angelaccio, 49, of Morton Grove, said she hopes police will show more restraint when she demonstrates at the overlapping G-8 and NATO gatherings.
"These are peaceful protests. And unless there is a need to respond in that fashion, OK, but I have not been at a protest when that has been needed," she said. She added she was encouraged by how Chicago police gave demonstrators an option of leaving or being arrested at a more orderly Occupy protest last fall.
Thistle Pettersen, a leader of Grassroutes Caravan, is planning to bring a group of 50 bike riders to Chicago to protest for a clean environment. The Chicago summits are getting a lot of buzz in politically active circles around the country and Pettersen said she expects big crowds.
"I've heard a lot of real, legitimate interest," said Pettersen, who lists her occupation as child care worker and folk singer.
The group has demonstrated at several political gatherings in recent years, and its members have to sign an agreement that they will not commit any acts of violence or property damage, Pettersen said. Still, she said that's no guarantee even groups like hers won't find themselves in the middle of a disturbance.
Citing the 2004 political nominating conventions in Boston and New York, she said the appearance of "agents provocateurs" who clashed with police at the end of otherwise peaceful marches may be an attempt to make mainstream demonstrators look bad.
"You've got to have your street smarts when you're out there and use your intuition," Pettersen said. "That's part of the risk of protesting in America these days."
Chuck Idelson helps organize the California Nurses Association, a union that has shown a large and steady presence in Occupy demonstrations, and said he expects that G-8 will draw the largest crowds of the year to demonstrate.
"The G-8 are, certainly, the countries that are the most prominent and, certainly, determine the direction of the largest economic powers in the world," said Idelson, whose group holds a permit for a demonstration and march on May 18, the day before the G-8 summit begins.
"One of the ways to put the most pressure on those who hold so much economic power is street heat ... many feel like it's the only way for regular people to have a voice anymore," Idelson said.
An Occupy demonstration in Oakland in January that started out peacefully took a volatile turn that left City Hall vandalized and resulted in about 400 arrests.But security experts said the benchmark for potential disturbances is Seattle's 1999 hosting of a World Trade Organization meeting, which was marked by violent protests and clashes between demonstrators and police. Many security experts expect crowds to be better coordinated than they were in those days, perhaps using smartphones to network in the field and guide movements.
Police Superintendent Garry McCarthy has said his department will work with federal partners, led by the U.S. Secret Service, to keep the city safe and open for business. Behind the scenes, police are drilling in formation and preparing for literally whatever protesters might throw at them.
The Secret Service will be overseeing security, with the priority of safely getting dozens of heads of state and other "protectees" from hotels and other sites downtown to the summits at McCormick Place convention center to the south.
"The main concern is ingress and egress — keeping them moving and on schedule," said Russ Collett, a former assistant special agent in charge of the Secret Service in Chicago who was on then-President Bill Clinton's detail for the WTO meetings in Seattle. "That's where their concern lies."
Chicago police will be expected to keep streets open amid protests or close them when motorcades need to pass, said Collett, now an executive at Lauren Innovations. Collett has been part of teams that coordinated the movements of President Barack Obama around Chicago just after his election in 2008, and said the Secret Service and Chicago police used the city's emergency operations center as a command post for motorcades and are well practiced.
One benefit of Chicago's layout is its street grid, he said, making it easy for every motorcade to have primary and secondary paths through the city around any protest hot spot.
Flexibility is built in, Collett said, and nothing is left to chance, as even before a movement starts each motorcade has a primary route, an alternate route, a known path to a hospital and safe house, and emergency landing sites for helicopters. The Secret Service will be most concerned with street movements around potential choke points where dignitaries will have to pass near areas of "public view" where they might have to pass close to crowds.
It's a certainty that police and federal agents are closely monitoring the Web and intelligence networks to try to predict exactly what protests groups could focus on Chicago.
"You have to understand who could be here and who could get into those areas of public view," he said. In the wake of 9/11, intelligence-sharing between federal agencies greatly improved, Collett said, and includes passing information to police who can use it on the street to look for problems.
City Hall has said large public spaces such as Grant Park, near the convention center, will be open during normal park hours. The city plans to work with protest groups to designate protest zones located within "sight and sound" of McCormick Place, city officials said — with the caveat that locations won't be set until the Secret Service outlines the security perimeters.
"My hope is we can have a dialogue to explore what they would like and what they think options are, so we can know their position and explore what-ifs," city Corporation Counsel Steve Patton said of demonstration groups.
Demonstrators fear the city may drag its feet on the issue until it's too late to mount a legal challenge before the summit. They don't want to be corralled in out-of-the-way locations where they have low visibility, such as how the city handled the 1996 Democratic National Convention.
Groups that wanted to protest at the convention had to take part in a lottery to dole out demonstration times in one-hour blocks. The designated demonstration area, also known as the "pit," was across the street from United Center where buses dropped off delegates. Another protest zone was in a massive parking lot a block away from United Center.
"It was like holding a rally for yourself," said Harvey Grossman, legal director for the American Civil Liberties Union of Illinois.
Tribune reporter Kristen Mack contributed.