Monday of last week, about 30,000 Chicago public school teachers went on strike. The ongoing walkout is directly affecting some 400,000 children across 700 public schools in the district.

The Chicago Teachers Union originally asked for a 35 percent pay raise, but the city government only offered 16 percent. The teachers say they are also striking over poor classroom conditions and alleged unfair teacher evaluations.

This year, the Chicago public school district plans to spend $5.11 billion, a major increase over last year. Nearly 50 percent of education dollars it receives from the state will go to teacher pensions by 2014, according to a report from the Illinois Policy Institute.

The union wants a change to the previous salary contract that has just expired. According to the Chicago Sun-Times, “The starting salary for teachers with a bachelor’s degree is $50,116 and $56,007 for teachers with a master’s degree. At the top of the scale, a teacher with a doctorate and 25 years of experience receives an annual salary of $127,649.” That was the previous contract. Now the Chicago Teachers Union wants a three-year pay raise with a 5.6 percent raise in the first year, a 6.5 percent raise the second, and another 5.6 percent raise in the third year.

The strike has gone into its second week, so Chicago Mayor Rahm Emanuel has sued the union in an effort to force the teachers back into schools. The teachers are enraged by Emanuel’s move and have pilloried his actions as undemocratic. As the days drag by, the strike gets messier and uglier.

There is also another story behind this strike that has not been as widely reported. The teachers unions are worried about losing out to private and charter schools.

Some Chicago lawmakers are trying to pass legislation for a school voucher program that would enable low-income parents to use tax funds at private schools as well as public ones. Similar voucher programs have been implemented in New York and Indiana with success.

A study from the Brookings Institute and Harvard University found that voucher programs in New York greatly increased the percentage of youths from low-income households of finishing high school and graduating college.

The demand for the Indiana voucher program has grown so much over the last two years that public schools are threatening to sue private schools that accept students with vouchers.

In Illinois, organized labor has stopped up voucher legislation for two years. If a voucher program is implemented, Chicago Public Schools and the Chicago Teachers Union are afraid parents will take their children to schools where teachers are accountable, students are safer, and students actually learn—and unionized teachers will be out of a job.

There is a problem with the education in the Chicago school district, that much is clear. Last year, the federal government found that only 50.2 percent of ninth graders within that district graduate within four years. With all of the money that is going toward education, where are the results? The teachers have been making salaries that are well above average. Will paying them even more money really translate into more students graduating from high school? Will it really do anything to fix the problem? Or will it simply be catering to greed?

That is the real story behind this strike. This isn’t about the welfare of the students—it is about the welfare of highly paid, unaccountable, unionized teachers. It isn’t about fairness and equality in labor—it is about selfishness and greed.