Chicago Mayor Rahm Emanuel is turning to the courts to force striking teachers back to the classroom.
Emanuel seeking an injunction to end the strike that's now entering its second week.
Both sides appeared to be headed toward a resolution Friday. This past weekend, teachers were expected to vote on a three-year proposal that included pay raises and a new method of evaluating teachers.
But on Sunday, union delegates decided to delay voting on the offer.
"We really need to take what was given to us today back to our membership, to give our membership a fair chance to make a decision," union delegate Erika Wozniak told reporters.
Chicago Board of Education President David Vitale decried the union's move.
"Just as we have said this is a strike of choice, it has now become a delay of choice," Vitale responded to the union's latest move at a weekend news conference. "Our kids cannot be used as pawns in internal union disagreements."
The teachers union will now wait until Tuesday to decide if they will suspend the standoff that's kept 350,000 students out of class.