The brinksmanship came just weeks after the two sides reached an agreement on hiring new teachers to allow for a longer school day. That issue once seemed to be the biggest roadblock to a new contract, but the bargaining and posturing has not let up as the two sides come down to the last few weeks before 400,000 Chicago students are all back in public schools.
"We have had 45 sessions of negotiations, and we're still pretty far apart," Karen Lewis, the teachers' union president, told the Board of Education at Wednesday's meeting.
Last week, the union began printing strike signs and made sure the media knew about it. On Monday, teachers started informational picketing at several elementary schools to make sure parents understood their issues - and to keep the contracts in the spotlight.
A union spokeswoman even hinted that if an agreement isn't reached, teachers might take their signs all the way to North Carolina to the Democratic National Convention, where Chicago Mayor Rahm Emanuel is scheduled to speak.
Behind the tough talk is a tense showdown between Emanuel and the teachers, with possible ramifications beyond Chicago at a time when most unions have seen their power slip dramatically. The mayor angered the teachers with his demands for a longer school day and other concessions, and the result appears to be an energized union that authorized a strike by a wide margin.
"Organized labor around the country is saying, 'What can we learn here? What clever moves can we emulate?'" said Timothy Knowles, director of the University of Chicago's Urban Education Institute. "And mayors are looking at Chicago and asking, 'Is Rahm going to pull this off?'"
School Board spokeswoman Becky Carroll declined to release details of the contingency plan the board essentially green-lighted Wednesday that authorized the district to spend $25 million if teachers go on strike.
She said the plan, which officials have been working on for weeks, will include providing a "safe environment" for the district's students and make sure the tens of thousands of students who rely on the schools for two meals a day will be fed during the strike.
Union officials say they're still concerned about job security for teachers and other staff, wages and health benefits. They also don't want to give anything away now, knowing it would be difficult if not impossible to reclaim anything in another contract.
State law requires the union to give a 10-day notice if it intends to strike. Union delegates voted Wednesday evening to authorize Lewis to present that advance notice at her discretion.
However, Lewis said in a statement after the meeting that no decision had been reached on whether to call a work stoppage.
"Although we have inched one step closer to fulfilling the legal requirements before we can strike, we have made no decision to do so at this time," she said.
A strike date would be set if and when the notice is given. Many students are already back in school, with the rest beginning on Sept. 4.
Lewis, who has repeatedly said that the 2 percent raise offered by the board is not acceptable, made it clear that she did not believe that the school district's financial picture was not nearly as dire as the mayor and the board members have said it was.
"Unfortunately, it's the same story year in and year out that there's never enough money," she told the board.
Lewis also suggested there were problems with the deal that calls for the district to provide more instructional time by hiring extra teachers so that current teachers won't have to work a longer day.
Outside the board meeting, Lewis told The Associated Press there was concern about counselors having to do lunchroom duty and reports that schools have not hired the music teachers, art teachers and others that the district said would be.
Carroll said Lewis' allegations were "just not true" and alleged that she was playing to the cameras.
"Kids are finally getting the full school day they deserve," Chicago Public Schools CEO Jean-Claude Brizard told the board. "We have come so far for the children of this city. We cannot turn our backs on them now."
To be sure, the city has toned down its rhetoric from the days last year when Emanuel in his push for a longer school day infuriated teachers by saying they students were getting "the shaft."
Back then, he persuaded lawmakers to write a special provision into statewide reforms that required only the Chicago Teacher's Union to get 75 percent of its members to authorize a walkout. The union then pushed up its vote to give retiring teachers a voice and the union leverage over the summer- proceeded to get 90 percent.
Some parents say it's difficult to know whom to believe but that they are expecting an agreement that keeps their kids in school.
"It would just be so unfortunate if a strike does happen," said Rasheda Muhammad, while back-to-school shopping with her 15-year-old daughter, Madinah, Wednesday at a Target store in Chicago.
Jeneen Lomax, who has one son who attends a public magnet school that focuses on science and math and one in private school, calls the possibility of a strike "devastating."
"They need to be exposed to as much learning as possible," she said.