A one-day protest in Oakland, California on Wednesday that involved more than ten thousand people was followed by police action in the early morning hours of Thursday, including the use of tear gas and rubber bullets, followed by dozens of arrests.

The demonstrations on Wednesday involved the participation of many workers and youth outraged over earlier police actions that led to the near-fatal injury of one protester, Iraq war veteran Scott Olsen, who was struck in the head by a projectile. The protests were among the largest organized by the Occupy movement against inequality in the US.

The day became a semi-official event, however, endorsed by the Democratic Mayor Jean Quan, who had overseen the police violence in the first place. The protests were coordinated with the trade unions, and police presence was largely absent during the day.

Mayor Quan issued a statement on Wednesday saying: “We have spent the week collaborating with the Port, county, school district officials as well as clergy, business, community and activity groups to ensure that the day goes smoothly.”

Around 11 pm, however, protesters started occupying the abandoned former offices of Travelers Aid Society, a non-profit organization for the homeless that shut down due to budget cuts. The aim of the “occupation” was to turn the building into a community center.

In response the police fired tear gas and rubber bullets at protesters, and encircled the plaza. By morning dozens of protesters were arrested and at least three were hospitalized.

Since the beginning of the port occupation there had been signs that the police were hoping for a provocation later. After dark a police helicopter had started circling the port shining its spotlight on protesters in the street. Since the street was already well lit with lampposts, this served no purpose other than keeping tensions high.

The actions of a few individuals who broke windows and engaged in vandalism were used as a pretext for police action. As is always the case with such actions, the operations of police provocateurs is likely. According to one eyewitness who spoke to the World Socialist Web Site, some people on the protester side of the barricades responded to the initial police advance in “bizarre and erratic ways.” Most notably one man “appeared sort of out of nowhere” and “broke the windows of some local businesses and tossed trash cans at the police.”

That was far more excuse than the police felt they needed to redouble their use of tear gas and rubber bullets. According to a city press release that afternoon, over 80 people were arrested.

There have now been more than three thousand arrests since the Occupy movement began in September. Elsewhere in the US on Wednesday, protesters in Rochester and Seattle were arrested by police under the Democratic mayors of those cities. Police in Rochester, New York arrested 16 protesters on Wednesday and over 50 since last Friday.

In Seattle under Democratic Mayor Michael McGinn, at least three people protesting the CEO of JPMorgan Chase at a Sheraton Hotel where he was a keynote speaker were arrested, and six people were arrested earlier that day outside a Chase Bank. In both cases, the police made heavy use of pepper spray on large groups of protesters.

Meanwhile, the occupation of the port in Oakland ended calmly Thursday morning when a local president of the International Longshore and Warehouse Union, Richard Mead, invited the last protesters to breakfast and the morning shift started work.

The march on the port and its “shutdown” was agreed upon beforehand by the union bureaucracy and Democrats as a safe way for protesters to vent their anger without raising any of the deeper political questions surrounding the police violence.

Together with organizers who support the occupy movement’s “no politics” approach, the unions sought to engender a carnival like atmosphere to the exclusion of any political discussion. Although many people brought amplifiers and speakers to the port, they were used for music. Notably absent from the rally was any central area to speak about the issues facing workers and discuss the political issues raised by the occupy movement.

None of the unions called an actual strike on Wednesday. However several, most notably the Service Employees International Union and the Oakland Education Association, encouraged their members to take personal days and join the rally with manager approval. Officials from these unions were involved in the organizational meetings to plan the event. Quan also invited city workers to take furlough days.

Absent from every unions’ solidarity statement was any mention of the Democrats or the role they are playing in cutting social services and supporting the rich. Typical were the statements of George Gresham, president of SEIU 1199, the union’s biggest local, and Gerald McEntee, president of the American Federation of State, County, and Municipal Employees, who told the Washington Post that they expected the Occupy Movement to support Obama in the next elections.