NEW YORK (AP) -- How can a movement that claims to speak for everyone turn anyone away? Occupy Wall Street is struggling with how to police unwelcome elements as sex arrests, hate speech and activists pushing causes from the Chinese Communist Party to gas drilling threaten to muddle its message.

The fires and shattered windows at protests in Oakland, Calif., a sex assault arrest in New York's Zuccotti Park and complaints of drug use elsewhere have drawn blanket statements from demonstrators against violence and unsafe behavior.

But to a large degree, the movement that welcomes everyone with a gripe against the system - any system - is embracing its fringe, saying protesters with causes unrelated to Occupy Wall Street are helping spur the revival of grassroots activism.

"From the very beginning, there have been many issues," said Bill Dobbs, a press liaison for Occupy Wall Street in New York. "Folks who had never thought of carrying a sign are out there on Broadway with signs about an issue that's important to them."

That includes Jimmy Chen, a mail man standing on a ledge at Zuccotti Park, his ankle tethered to the edge of a huge banner reading, "Just say No, Chinese Communist Party." He says the party is as corrupt as Wall Street and claims it even gives it money.

Antiwar signs also circle the tents in the Financial District, along with pleas to pay health insurance to ground zero workers, and for Pennsylvania to ban hydraulic fracturing, the controversial technique of injecting water and chemicals into the earth to drill for natural gas.

Several protesters objected to a sign weeks ago reading "Zionists Control Wall St," prompting letters from the Anti-Defamation League, but the movement has made no mission statement banning hate speech or any kind of speech.

In Washington, an antiwar group that began camping in a park in early October became publicly confused with an Occupy Wall Street encampment, and the two have gotten into spats over whose right it is to use the name. The groups now say they coexist peacefully and speak for much the same thing.

In Portland, Ore., many protesters complained of drug use, the presence of homeless and mentally ill, and the mayor wrote a letter to the movement this week warning the camp to control its behavior.

Protesters of Occupy Portland recently proposed limiting the number of people in camp to those who contribute to committees, but the idea went nowhere. Many said it was antithetical to the movement.

The movement is "walking the walk" and espousing its message of inclusion by allowing in anyone, provided they are not violent or disruptive, Portland organizer Reid Parham said.

"We let in former criminals, people who have criminal records," he said. "There's no use in locking them out if they have served their due process and served any judgment against them."

There's precedent in most grassroots movements to attract hangers-on and demonstrators seeking to publicize other causes or alter the message, including the antiwar and civil rights movements, activists and experts say. But Occupy Wall Street, priding itself on being leaderless and not subscribing to one unified voice, will struggle more to define itself against that backdrop, experts say.

"There have been other movements that are more disparate," said Mary Frances Berry, a University of Pennsylvania history professor and former chairwoman of the U.S. Commission on Civil Rights. "Most of them have specific goals. Most of them have identifiable leadership. ... Therefore, you didn't have this incoherence."

Berry, one of the founders of the Free South Africa movement in the 1980s, remembered a man who joined a protest with a sign protesting pedophilia by priests, while they lobbied for anti-apartheid measures.

"He would stand across the street with his sign," she said. "We didn't try to stop him. He was over there and he was doing his thing. People would show up with signs about poverty. ... We were clear because we had goals."

Dobbs, representing protesters in Zuccotti Park, said the movement espouses nonviolence and confrontations with police. The 1,000 or so arrests in New York have involved mainly trespassing charges. But "social change is never neat and pretty," and most of the movement continues to be focused on income inequality and anti-corporate greed, he said.

Zuccotti Park's encampment is relying largely on self-policing, with a self-styled security force that protesters can call when they're in trouble.

"Everybody's trying to take care of each other," said Rae Altman, 28, who came from Portland, Ore., to camp in New York. "If you don't know how to handle something, you can call out."

The protesters also call the police, resulting in last week's arrest of a 26-year-old man on charges he groped a teenager.

But demonstrators say the point of their protests is not unity of position, but in generating discussion. In Washington's Freedom Plaza, members of October2011 Stop the Machine held daily seminars on topics ranging from clean energy to food and water, transportation and the media.

The group initially began a protest to mark the 10th anniversary of the U.S. war in Afghanistan but has since pledged allegiance to Occupy D.C., even directing its website to the same domain name. A member of Occupy D.C.'s liaison committee, Janelle Treibitz, said the group was asked to keep a separate name.

In New York, diverse opinions on any cause are welcome, said Altman and her husband, Aaron. They said they left their jobs as bakers and baristas to learn about America and rejoin a community that has stopped debating its problems.

"This is an open space," Aaron Altman said. "If you have a problem with this current system, you can come to this open space.

"It's just a big conversation."

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Associated Press writers Nigel Duara in Portland, Ore., and Ben Nuckols in Washington contributed to this report.

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