A pile of discarded sleeping bags, blankets, pillows and posters took up nearly half a room in Occupy Chicago's headquarters last week, left behind by protesters who traveled to the city last month for the NATO summit.

But a few rooms over, some of the group's core members were back at work, painting a new banner and discussing how to refine their tactics and goals now that the summit — and the worldwide media spotlight that accompanied it — has come and gone.

"I would say we're the strongest we've actually been since the beginning," said Matthew McLoughlin, 26, sipping coffee as he sat with two other Occupy members at a table in the group's fifth-floor loft in a massive East Pilsen warehouse. "I think we did an excellent job of getting our messages out there, and I think people are more motivated than ever to keep that going."

Whether the group can build off that motivation this summer remains to be seen. Many of Occupy Chicago's members say they are now focusing more on local issues rather than on national and global problems, a shift that experts say mirrors those made by Occupy groups in several other cities.

"We've had NATO looming over us since we started," Rachel Unterman, 29, said Tuesday as she waited for a downtown rally and march to begin. "It was kind of like a goal to work toward, and I think we'd do well to find (another) one."

Only about 30 people joined Tuesday's march, walking from the Chicago Board of Trade Building to the Thompson Center, City Hall and President Barack Obama's campaign headquarters to demand that authorities pay for medical and therapy bills that some protesters say they incurred as a result of clashes with police before and during the May 20-21 summit.

Police officers on bicycles kept an eye on the protesters as they marched through the Loop, but the scene was a far cry from the largest protests during NATO, when thousands of protesters spilled into the streets and blocked traffic, their chants echoing off downtown skyscrapers.

Instead, the group waited for walk signals before crossing most intersections, and their chants ebbed and flowed in volume. Most passers-by gave the protesters only a brief glance before continuing on their way.

But several members of Occupy Chicago cautioned that judging the movement by the number of people who show up for a midday march doesn't accurately gauge the group's strength.

When a show of force is needed, the group's members usually deliver, said Rachael Perrotta, who often speaks to the media on behalf of Occupy Chicago.

"They will not participate every day," Perrotta said. "They will not participate every week. But when we have something big, they will come out in the thousands for us."

Occupy Chicago positioned itself as a key component of the local opposition to NATO, helping out-of-town protesters find travel and lodging and helping to organize mass protests. They publicly supported protesters who were arrested during the summit, including five people facing state terrorism or explosives charges.

Despite the focus on NATO, the group has also lent its support to local causes by fighting efforts to close some mental health clinics and aligning itself with the Chicago Teachers Union during its contentious contract negotiations.

Several members said those efforts will continue, but they said the group also plans to ramp up protests outside the Obama campaign headquarters at One Prudential Plaza, hoping that their efforts will play a role in the presidential election.

The range of causes embraced by Occupy Chicago and similar groups in other cities can be confusing to outsiders, but the groups are often simply trying to find causes that will generate the most attention and support, said David Meyer, a sociology professor at the University of California at Irvine.

"When it's working for Occupy, they're all broadly under this banner of rectifying inequality," Meyer said. "There's a lot of experimentation that's going on."

Jeffrey Troutman, 31, said he hopes that moving beyond NATO will help Occupy Chicago readjust its focus as the summer approaches.

"It was a lot of pressure and a lot of organizing responsibilities that I'm glad to be done with," Troutman said during a break from Occupy Chicago's twice-weekly general assembly meeting in Grant Park on Wednesday, which drew about 30 people.

"The conversation we're starting to have here — who knows where it's going," he said. "It's more diffused, but it's stronger than you can see in any one spot."

rhaggerty@tribune.com Twitter @RyanTHaggerty