UPDATED 06/06/12 – 4:38 p.m.

CHICAGO (CBS) — Chicago Public Schools teachers began voting today on whether to authorize a strike.

It’s a vote CPS Chief Executive Officer Jean-Claude Brizard called premature.

But as CBS 2′s Derrick Blakley reports, the symbolism of the vote might be just as important as the substance.

It’s a vote that gives union bosses the power to call a walkout. A successful vote would also give the union more leverage in contract talks with the city.

“This vote is about getting leverage at the bargaining table, and that’s designed to try to get the school district to provide for a better day, not just a longer day; for fair compensation for the people who work in the schools; to ensure class sizes; and to ensure a measure of job security for the people who work in the schools,” CTU vice president Jesse Sharkey said on the CBS 2 Morning News.

But the vote is also a rallying cry for frustrated, fed up, furious teachers.

CTU President Lewis was warmly greeted by fellow union members Wednesday morning at King College Prep High School, 4445 S. Drexel Blvd. In front of a gaggle of media, Lewis then slid her ballot into the envelope being used as a ballot box at the school, where she used to teach.

LISTEN: WBBM Newsradio’s Bernie Tafoya reports

King College Prep High School teacher Elias Yurick said, “I think that they’re trying to play hardball, and we’re going to have to play hardball back.”

To authorize a strike, 75 percent of all Chicago Teachers Union membership must vote yes on a strike. That alone would be a resounding rebuke for CPS leadership.

If teachers do not authorize a strike, a walkout is not a legal option for the union under state law.

But Brizard has insisted the vote should wait until an independent fact-finding panel issues a report that could serve as the basis for a contract compromise.

“Teachers are being asked today to make a decision, based on incomplete and very often grossly inaccurate information. We’re in the middle of negotiations. Why do it now?” he said.

Brizard said the vote was rushed by the union. He said the authorization vote would have been more appropriate if it had been held in the last week of August. That way, Brizard says, retiring teachers wouldn’t have voted Wednesday on a deal that he says won’t actually affect them.

But Lewis asked, “Why wait? Why wait? We can’t wait.”

She also said an independent fact-finder’s report that has been characterized as a “deal” will not include everything.

“Fact-finding is not going to write us a contract,” Lewis said. “Fact-finding is going to put out four or five pieces of information as best.”

Lewis said a last-minute letter Brizard sent to teachers on Tuesday, asking for a no vote, was a desperate move by the school district.

“I read the letter. It was actually rather sad,” she said.

Lewis also spoke firmly about the value of a strike authorization vote as a bargaining chip in negotiations.

“We need to make some movement at the table. They need to understand that now, we have the voice of 30,000 people at the bargaining table with us, and it has to be done. And it has to be now,” Lewis said.

Negotiations began in November, but the two sides remain far apart, and after voting, Lewis – a former math teacher – explained up her demand for a 29 percent pay hike, given the push for a longer school day, and the Board of Education’s decision not to give teachers promised raises last year.

“Our workday has increased 20 percent, so we asked for that. They stole 4 percent from us last year, we asked for that. And then we want a 5 percent raise next year,” she said.

The union is seeking a 29 percent raise, but the district is offering just 2 percent.

Not all teachers believe their union’s demands are reasonable.

King High School teacher Ashlea Monti said, “Here, I think that the teachers do deserve a raise. Would I say that for other schools? Not Necessarily. That’s just my opinion.”

Monti said she supports merit-based pay for teachers, something union leaders oppose.

If teachers authorize a strike, Lewis couldn’t call an actual walkout on her own. Teachers would get another chance to vote to strike, should contract talks break down.

Any strike would be the first walkout by Chicago teachers in 25 years.

The authorization vote continues at least through Thursday, possibly Friday. Union officials aren’t expected to announce results until the vote is over.

It is expected to be at least a couple of months before a walkout occurs if teachers authorize a strike.