The public school teachers union says it might prepare for a strike vote or continue a legal challenge to a contract offer imposed in July if members do not ratify a proposed six-year pact today.

In an interview with the Star-Advertiser Wednesday, Hawaii State Teachers Association President Wil Okabe said that while he remained optimistic that the tentative agreement will be ratified, the union will be ready with options if the deal is rejected.

"We expect a positive ratification vote," he said.

In a letter to teachers Wednesday, Okabe said the vote "will chart our course for the next several years."

"The HSTA board believes that the contract before you is far better than what any other public sector union has achieved. That doesn’t mean you have to vote to ratify the contract."

Okabe told members if a majority of teachers vote "no," the union’s options are to live with the two-year, "last, best and final" contract offer the state imposed in July, strike "to force the state to make us a better offer this year" or continue with a prohibited-practice case that is before the Hawaii Labor Relations Board.

Teachers will begin voting on the proposed contract at 3 p.m. today at polling places statewide, and results are expected as early as 9 p.m.

Teachers have had mixed opinions on the contract, with some raising concerns about the move in July 2013 to a performance-based system that rewards "effective" teachers with raises.

John Nippolt, chairman of the art department at Kalani High School, opposes the deal and said he will wear a paper bag over his head and hold a sign that reads, "Occupy, not ratify," when he votes against the proposed contract.

Nippolt said he has heard from a number of teachers also angry about the agreement. "We’re saying no to this," he said.

Whether vocal opposition from Nippolt and others will translate into enough "no" votes to spike the deal isn’t clear.

Never before has HSTA’s membership failed to ratify a proposed contract supported by the union’s executive board, as this contract offer has been.

"Right now, it’s in the hands of the membership," Okabe said Wednesday, when asked about the opposition.

Under the proposal, teachers, like other public workers, would continue to see 5 percent wage reductions through June 30, 2013, before moving to a new salary schedule that recognizes their years of service with the state Department of Education. The department also would move to a revised teacher evaluation system, and teachers rated "effective" or "highly effective" would be eligible for 1 percent "step" raises annually.

If approved, the new contract would run retroactively from July 1, 2011, through June 30, 2017.

The six-year deal is aimed at ending the months-long labor dispute that has placed at risk Hawaii’s $75 million federal Race to the Top grant.

Delays in reaching collective bargaining agreements on key reform issues, including new teacher evaluations, have been blamed in part for the U.S. Department of Education’s decision last month to place Hawaii’s Race to the Top grant on "high-risk" status.

If teachers don’t approve the new deal today, the state will be left scrambling to figure out its next steps, as it works to show the Obama administration it can make good on its ambitious education reform pledges.

Since details of the proposed contract were released last week, several teachers have said they are disappointed about the continued wage reductions, while others have reservations about approving a performance-based pay-raise system without knowing what the new evaluations will look like.

The evaluations will be based in part on a teacher’s influence on student academic growth, but the details on how progress will be measured aren’t yet clear.

In a letter to complex area superintendents this week, which was shared with HSTA members, Schools Superintendent Kathryn Matayoshi reiterated that the "teacher evaluation system will be based on multiple measures, and a teacher’s final rating will not be based solely on a single measure, including standardized tests."

If the new deal is ratified, the union has also pledged to drop its prohibited-practice case.

HSTA sought relief through the labor board this summer, after the state imposed its "last, best" offer, which included pay cuts, furloughs and higher share of health insurance premiums.

Proceedings have dragged on for months, as the union has argued the state violated members’ rights in imposing a contract. The state has said the action was needed to preserve hundreds of teachers’ jobs.

The state’s decision to unilaterally implement its "last, best" offer for its 12,500 teachers was unprecedented in Hawaii public employee bargaining.

Withdrawing the labor board case would mean the question of whether the state has the right to impose a contract will remain unanswered, at least in the short term.

The University of Hawaii Professional Assembly, which joined as a party in the labor board case, said it would not pursue the question if the case is dropped.

Joan Husted, former HSTA executive director, said she is not surprised HSTA agreed to withdraw the case if the contract is ratified. She said the governor may have said something in talks "to make them reasonably comfortable" that a contract would not be imposed again.

Meanwhile, Husted is predicting ratification.

"There’s sufficient good stuff" in the deal "and a few trouble spots," she said. Among the problems, she said, are the unknowns over what the revised teacher evaluations will look like and how the student growth will be measured.