AUSTIN (AP) – The failure of a critical school finance bill puts Texas lawmakers in the likely position of having to work overtime.

Democrats used a filibuster — the last weapon in their arsenal — to block the bill early Monday morning after 139 days of fighting budget measures that slash billions of dollars in state funding from public education and other areas.

Sen. Wendy Davis, D-Fort Worth, began talking late Sunday night and talked until midnight, preventing a Senate vote on a bill that would have allowed Texas to pay public schools $4 billion less than owed under current law. The House had passed the bill a few hours earlier.

Republican Gov. Rick Perry had warned lawmakers earlier Sunday that he would call them back into a special legislative session Tuesday if the bill failed. The regular session ends Monday.

The Senate could still take up the bill Monday, but that would require at least 25 of the 31 senators to agree, a scenario several Democrats said was unlikely and one that Republican Lt. Gov. David Dewhurst didn’t want to predict.

“I am personally, really disappointed,” Dewhurst said. “This puts the budget in a crisis.”

Davis was unapologetic over her maneuver.

“Priorities of hard-working Texas families have come dead last this session,” Davis said. “This is a tool that we had, and I’m proud to have used it on behalf of the people I represent.”

Republicans could do nothing to stop her when she launched into the filibuster late Sunday. Facing a midnight deadline, the Senate didn’t take up the bill until after 10 p.m. By the time Davis started, she only had about 75 minutes to go to meet the midnight deadline and cut off the bill without a vote.

“We have failed our school children,” Davis said when she began. She then read letters from constituents in her district — students, parents, teachers — much like actor Jimmy Stewart in the 1939 movie “Mr. Smith Goes to Washington.”

After the deadline passed, Davis’s eyes began to tear up and she left the Senate chamber with Sen. Rodney Ellis, D-Houston.

Some Republicans mocked the filibuster, saying it was pointless. If Perry calls lawmakers back into special session, Republicans have a 19-12 Senate majority to brush aside Democrats.

Sen. Florence Shapiro, R-Plano, who had negotiated the schools provision, predicted the bill would eventually pass. She called Davis a “lone ranger” and said she believes the Senate could rally the 25 votes needed to pass it Monday.

The schools provision would change distribution formulas to public schools so the state could legally give them less money under the new budget. It would spread the $4 billion shortfall over the two years of the budget period — 6 percent across-the-board cuts in 2012 and $2 billion in targeted funding levels in 2013.

Rep. Mike Villareal, D-San Antonio, said if the bill passed, Texas would drop from 44th in the nation in student spending to 46th.

The bill’s failure also complicates the overall state budget bill, which made $37 billion available to public schools if senators passed the new funding formula. Without the bill that failed Monday, that money is stripped from the budget.

The bill’s failure puts a messy end on a contentious legislative session dominated by emotional battles over the budget. On Saturday, the House and Senate passed a budget that slashed billions of dollars in funding to public schools, higher education and health care services.

Democrats have fought to use more money from the state’s almost $10 billion reserve fund to pay for public schools, a move Perry and other Republican leaders have rejected. Republicans argued that the cuts lawmakers made in all areas were tough but necessary. They said the state simply didn’t have the money, even though lawmakers left billions in the reserve fund.

“I hope we never have to go through what we had to this session again,” said Sen. Robert Duncan, R-Lubbock.

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