Outside Tarkington Elementary Tuesday, hundreds of striking teachers shouted, some banged on buckets.

You could still hear them inside the school’s media center. That’s where Mayor Rahm Emanuel repeated what he’s been saying since teachers walked off the job: he wants to hold principals accountable for their schools’ performance. And to do that, he has to let them pick their teachers.

“You can’t say to a principal, ‘Why did your test scores go like this?’ Then you say, ‘Well, you made me hire this teacher. Rather than the teacher I wanted to hire.‘”

This issue of job security is important to the teachers union because Chicago has been trying to fix its schools by closing them. Over the last decade, the city has shut down or fired everyone at more than 100 low-performing schools. Thousands of teachers have lost their jobs. The union fears 100 more closings. District officials have said that’s not true.

That’s why the teachers union is fighting for a provision that would force principals to hire those laid off teachers.

That doesn’t seem right to Mahalia Hines. She was a Chicago teacher for 17 years, then a principal for 17 more. Now she’s a member of Chicago’s Board of Education. She joined Emanuel yesterday.

“I know when teachers were just sent to my school, and I had to accept them, regardless. They were sent from downtown,” said Hines. “That was one of the most difficult times in my life as a leader. I was so happy when that change came about.”

That was in 1989, after Chicago’s schools were dramatically decentralized.

“All along when we were principals, teachers  lost their jobs. This isn’t new. As a new teacher I lost my job. But guess what? I was good. Good teachers are able to get jobs.”

Surrounding Emanuel were a handful of principals who agreed with him and with Hines. Maria McManus is principal at a new magnet school. She hired a teacher whose school was shut down. 

“And she was phenomenal,” said McManus. “She came in as a third grade teacher. And she ended up being great, and now she’s my science specialist this year. I have no problem with that, but I was able to select her. She wasn’t forced. They didn’t send me a list of people and say, ‘Hire one of these.’ I interviewed hundreds of people and she just happened to be the choice.”

The district’s expired teachers’ contract gives teachers 10 months at full pay to find another job. CPS says about two-thirds of teachers eventually do find jobs.

Jackson Potter is with the teachers union. He says the district’s school closings create instability—and chase away great teachers.  He says principals already have to hire teachers with the correct certification and good evaluations.

“If you have a teacher who meets all that criteria, and through no fault of their ownt hey’ve been displaced, and the principal has a pick of three or more of those applicants , they should be required to hire one of those people. Those people have proven themselves, that they’re capable of doing that work, and you shouldn’t kick them to a curb. We’re losing too many experienced educators.”

And the union is losing members. Over the past eight years, the number of teachers in the union is down by 22 percent.

School board member Hines says that doesn’t mean that those teachers are no longer working.

“It doesn’t mean they’re not in some of the charter schools, and it doesn’t mean that they’re not in the suburbs. I still say good teachers will be hired.”

But with the number of district schools shrinking, the odds of being rehired at a Chicago Public School are getting worse.