On Sept. 10, the Chicago Teachers Union went on strike after it could not reach a contract agreement with Chicago Public Schools, robbing students of vital class time. Both sides should have come to an agreement before classes started.

Chicago should always stand by its teachers, but both sides have let students down by taking so long to forge an agreement. Hopefully, this strike has taught CPS and CTU not to fight their battles using students as weapons.

The most troubling issue in dispute was how teachers will be evaluated, hired and fired. CPS wanted to make it easier for school principals to hire and fire teachers based on student success. It’s a good idea on paper, but CTU believes 6,000 teachers could lose their jobs in the first two years of these changes because of substandard test scores. An Illinois law passed in 2010 mandates that student performance on standardized tests must make up at least 25 percent of teacher evaluations; CPS wanted student performance to account for 40 percent, according to the Washington Post.

Test scores are not a reliable measure of an individual teacher’s competence in a school district with overcrowded classrooms and inadequate resources. Last year’s Prairie State Achievement Examination, the test taken by all Illinois high school juniors, showed that only 31 percent of all test-takers in the district met or exceeded standards. Teachers are on the front lines of education, but low districtwide test scores implicate other factors including class size and parent involvement.

Many teachers have already lost their jobs because of school closures, and the mayor and CPS want to make it easier to replace them. Of course, there are times when teachers are underperforming and need to be fired, and unions have become notorious for getting in the way of their termination. But contract language that sets standards for hiring and firing is important to protect workers from unfair labor practices. Having a say in how schools are staffed is vital to keeping conditions fair for teachers. This may not resonate with Mayor Rahm Emanuel, who favors non-unionized charter schools as a panacea for Chicago’s failing schools.

The biggest blunder of the negotiation process has been the public feud between Emanuel and union President Karen Lewis. During negotiations last September, Emanuel allegedly said “f–k you” to Lewis, and on Sept. 2, Lewis called Emanuel a “liar and a bully.” Emanuel has not attended recent negotiations, even on Sept. 9, when a strike was imminent, because of bad blood between him and Lewis. Students have been missing out on classroom education, and they are being taught the wrong lesson about problem solving. If the adults in charge of the school system can’t even talk to one another, why are they being trusted with decisions that affect so many children’s lives?

Teachers should always have the right to fight for their profession. Small class sizes, improved classroom conditions and a fair teacher evaluation system are all issues that will have a major impact on the success of Chicago students. A strike may have been necessary, but negotiators should never have let it reach that point. Pulling teachers out of the classroom, regardless of who is “in the right,” has serious consequences. Neither party should feel like a winner for doing that.