The Chicago Teachers Union (CTU) has announced their strike will continue into Friday–despite an offer from Jesse Jackson to mediate–after CTU President Karen Lewis said she’s “optimistic, but we’re still hammering things out.”

At the heart of the standstill is accountability: merit pay, the evaluation process, and how appeals over “unsatisfactory” ratings will be considered.

According to Crain’s Chicago Business, after the latest round of negotiations, merit pay is now “off the table” and the city has given in on the formula for evaluating teacher performance. Chicago Public Schools had wanted 40% of a teacher’s evaluation to be based on “student growth,” but now has put forth a plan that cuts this to 35%, with another 20% based on students’ test scores. From Crain‘s:

…It will be more difficult to dismiss teachers who get unsatisfactory ratings than it would have been under CPS’ original proposal. Under the proposal the board made Wednesday, no first-year teacher rated “unsatisfactory” can be dismissed. And in later years, they will have a right to appeal an unsatisfactory rating. The appeals process will be developed in further talks….Overall, it appears to me that CPS has given more than the union — so far. But the issue of recalling laid-off teachers remains yet to be resolved, as of this writing.

CTU would like to change the strike narrative from one of accountability and merit-based pay (they are the highest-paid teachers in the country with an average salary of $76,000 plus benefits) to air conditioining and the number of social workers. In order to do this, the CTU is both playing up the “Air Conditioning” theme while also framing accountability measures as overly reliant on testing. As the offer now stands, only 20% of teachers’ evaluations are based on testing, but you wouldn’t know that from the rhetoric CTU is pushing.

Bill Ayers’s colleague Isabel Nunez, a local professor of “foundations and social pay,” certainly is playing along. She penned an editorial today in the Chicago Sun-Times ridiculing conservative think tanks’ support of testing as “madness,”  writing:

Thank goodness the Chicago Teachers Union is standing up to this madness. Teachers, working people and concerned citizens around the country are watching you, like heroes on a movie screen, with hope.

After a rally today (watch livestream here) outside Chicago School Board Member Penny Pritzker’s family hotel, Hyatt, their largest protest yet is planned for Saturday. Occupy is helping get the word out.

And still, President Obama, who promised in 2007 that he’d “walk that picket line with you,” has yet to show. He never showed up in Wisconsin, either.