CHICAGO (CBS) — Mayor Rahm Emanuel was standing firm Wednesday on the two biggest roadblocks in the Chicago teachers’ strike: teacher evaluations and principals’ discretion over teacher hiring.

The mayor has been getting widespread support from aldermen, but said he’s not willing to use a possible legal hammer to force an end to the strike, at least not yet.

CBS 2’s Derrick Blakley reports the mayor contended the union’s two biggest concerns in contract talks – a new teacher evaluation system and allowing principals unfettered hiring power – are not issues the union can legally strike over, under state law.

But Emanuel said he’s not ready to drop the legal equivalent of a nuclear bomb by challenging the legality of the strike before the Illinois Educational Labor Relations Board, or by going to court to seek an injunction to force an end to the walkout.

“I believe we should work it through at the table, that’s why our team is there, and working through all those issues,” Emanuel said after Wednesday’s City Council meeting.

Aldermen have been backing the mayor on many of those issues, like teacher evaluations.

Ald. Latasha Thomas (17th) said, “We evaluate our students with tests. So [teachers’] evaluations has to have something to do with how the students are doing.”

Most aldermen also appear to back Emanuel’s push for principals to have the right to hire any teacher they want at their school, not just those who have lost their jobs due to school closings, or other reasons.

Ald. Proco Joe Moreno (1st) said, “I wish the union was more interested in promoting and rewarding good teachers than protecting bad teachers, and that’s what it comes down to.”

But some aldermen sympathize with teachers’ call for more school counselors and social workers, and Ald. Robert Fioretti (2nd) accused the mayor of demonizing teachers.

“These are the first line of defense that we expect our kids to help, to move our kids forward in the city. What are we talking about? I mean, and then all of a sudden, they’re the demon?”

But the mayor stopped short of ruling out a legal challenge to the strike if it drags on.

“That’s an if, and I don’t answer hypotheticals,” Emanuel said.

The mayor said he hopes everyone at the table shares the same sense of urgency he holds, and he still contended there’s no reason the two sides could not have kept talking, while teachers continued teaching, and kids continued learning.