Police arrested 57 protesters for disorderly conduct Thursday outside Washington Square Park, bringing an abrupt end to a union rally conducted by dozens of New York University graduate assistants.

Members and supporters of the Graduate Student Organizing Committee, NYU's unrecognized union of GAs, sat down in the middle of Washington Square North in what spokeswoman Susan Valentine called a "demonstration of GSOC's continuing commitment."

The New York Police Department, which had been tipped off about the planned act of civil disobedience, was waiting for the protesters when they arrived. Forty-three union members and 14 supporters were taken into custody and were released on Thursday evening.

Earlier in the afternoon, union supporters met at Judson Memorial Church on the south side of the park to hear speeches from Bill Thompson, city comptroller, and John Wilhelm, co-president of labor organization UNITE HERE. Members also certified a union petition in support of the strike, signed earlier this month by 500 of GSOC's 900 members.

About 200 GAs have remained on strike since Nov. 9, 2005, protesting NYU's decision not to re-certify its expired collective bargaining agreement. Previously, the union had been protected by the National Labor Relations Board, but a 2004 NLRB ruling overturned precedent and declared that graduate students did not qualify as workers.

In August 2005, the university, relieved of its legal obligation to recognize the union, declined to renegotiate GSOC's contract on favorable terms. Union members voted to strike shortly thereafter. The protestors' arraignment is scheduled for May 23, 2006.