About two hundred protesters, many dressed in red, gathered in Union Square on Monday evening in solidarity with the thousands of Chicago teachers who went on strike Sunday night after a failed negotiation for a new contract.

Chicago Public Schools and the Chicago Teachers Union have been mired in disputes with the city for several months over wages, benefits, teacher training, the lack of class size regulations and the need for more air conditioning in all schools, amongst other issues.

The strike left about 350,000 students without classes on Monday in the nation’s third-largest public school district. A contingency plan has already gone into effect; since yesterday, most students spent half-days on school campuses with supervised activities and a meal.

Illinois is one of the few states in the country that does not have a limit on class sizes due to the 1995 Illinois Educational Labor Relations Act, which prohibits the Teachers Union from bargaining over the issue.

“[Chicago teachers] are on strike fighting for public education and to protect the future of our schools,” said Megan Brenn, a New York City public school teacher and member of the United Federation of Teachers, who attended the protest in Union Square. “I’m sure I’m not the only teacher who, after years of teacher-bashing on a daily basis, felt she could hold her head a little higher today.”

“Chicago teachers are taking a stand against the ‘blame the teacher’ rhetoric and against the corporate driven, so-called reformers, who have decimated public education in this country,” Brenn added. “Their fight is our fight as long as it continues.”

A widespread concern among the protesters was the implementation of annual standardized tests, which became mandatory under the No Child Left Behind Act of 2001. Many said the tests provide an inexact and skewed barometer to measure the effectiveness of teachers in the classroom.

“Across the United States they have devised these really stupid teacher evaluations that depend on test scores,” said Laney Hanson, an activist and parent living in New York City with children in public schools. “All of the studies show, including the National Academy of Sciences, that teacher evaluations based on test scores is unreliable.”

Many of those present at the rally were not teachers or educators, but current and former students who came out in support of American educators.

“Teachers are important. They educate the next generation,” said Jenna, a freelance photojournalist who attended the rally and preferred not to give her last name. “I just moved here from Wisconsin and we just went through something pretty similar, and a lot of Chicago teachers came and supported us in our struggle. I figured it was my turn to show up.”

Chicago Mayor Rahm Emanuel has said that improving the city’s schools is one of his top priorities – but added that the Teachers Union work stoppage represents “a strike of choice.”

Emanuel’s three children attend University of Chicago Laboratory Schools, a private institution which prides itself on “teachers [who] develop a warm and sharing relationship with their students by maintaining a low-student teacher ratio,” according to the school’s official website.

Hanson, who spoke at the rally, received cheers from the crowd when she said, “I don’t understand why there is one education system for the rich and one for everyone else.”