The historic teachers’ strike in Chicago has entered its third day as educators remain deadlocked with the city over teacher evaluations and other issues. On Tuesday, thousands of Chicago Teachers Union members flooded Daley Plaza outside City Hall and marched toward the school district’s headquarters. Nearly 30,000 teachers and their support staff have walked out over reforms sought by Chicago Mayor Rahm Emanuel, who is President Obama’s former chief of staff. A key point of contention is the district’s proposed method for evaluating teachers, which the teachers’ union says relies too heavily on standardized testing and could soon result in thousands of job cuts.