Early Sunday morning, the New York Police Department (NYPD) arrested over 70 demonstrators who were commemorating the six-month anniversary of the start of Occupy Wall Street in Zuccotti Plaza in Lower Manhattan. On September 17 a few hundred young people began camping in the plaza to protest the domination of American politics and the economy by the banks and corporations.

In the most recent protest, demonstrators marched through Manhattan’s financial district and past the New York Stock Exchange chanting the now-familiar, “We are the 99 percent.” Hundreds assembled in the plaza nearby during the afternoon and evening in a peaceful and largely festive gathering. The NYPD removed one structure—protesters say it was a banner—that had been erected and lined the streets adjacent the plaza in a show of force. At 11:30 p.m. a police commander ordered the protesters to disperse and most began leaving.

Shortly after midnight, uniformed and plainclothes police moved into the plaza en masse and began to handcuff people. Other officers swung their batons. Some protesters linked arms and police tackled others to the ground as they pushed into the crowd. Video footage shot of the assault shows police tackling more than one peaceful protester. Many were taken into custody in police vans while a city bus was called into service to remove others.

One woman. Cecily McMillan, suffered a seizure after police threw her to the pavement and had to be taken to a hospital.

NYPD spokesmen have asserted that the protesters had broken park rules by bringing in tents and sleeping bags. According to the Washington Post, Sandra Nurse, a member of Occupy Wall Street’s direct action working group, denied that protesters had been prepared to occupy the plaza and pointed out that they had neither sleeping bags nor tents.

Demonstrators have alleged that the NYPD used excessive force and called for an official investigation into the department’s actions.

The occupation that began on September 17, 2011 opposed the oligarchic rule of the richest one percent of the American population. The encampment, and the many protests associated with it, struck a chord with millions around the world who have experienced a relentless assault by the ruling elite on jobs, living standards and democratic rights.

In subsequent days and weeks, the protest began to receive international attention and broad popular support. Support grew especially after the NYPD started making mass arrests of protesters, first in Union Square on September 24—where Deputy Inspector Anthony Bologna was videotaped gratuitously pepper-spraying young women—and then on the Brooklyn Bridge on October 1, where over 700 were arrested in what many have alleged to be an act of police entrapment.

As hundreds of Occupy encampments sprung up around the world, the authorities, particularly in the United States, and often at the behest of Democratic Party mayors, responded with violence to close them down. This included the use of tear gas and rubber bullets in Oakland, California, Denver and elsewhere. One protester in Oakland suffered a near-fatal injury in the police violence. The New York police violently evicted the original encampment form Zuccotti Park on November 15.

The emblematic act of brutality came on November 19 at the campus of the University of California, Davis, when a university police officer systematically pepper-sprayed seated, peaceful students at a protest.

In recent weeks Occupy activists have complained of surveillance by the NYPD that goes well beyond the now habitual videotaping of protests themselves. According to the New York Times, one Occupy organizer said that on December 16, “officers parked outside her home in Bedford-Stuyvesant, Brooklyn, where people were discussing a demonstration planned for the next day. … Another found uniformed officers outside her apartment who told her they were there to conduct a ‘security check’ for a condition they would not identify.”

These allegations come on top of revelations that the NYPD conducted massive surveillance of Muslim groups well beyond the borders of New York City, particularly on college campuses and at social activities.