JEFFERSON CITY — In an early morning vote that had to be done not once, but twice, the Missouri Senate today passed a bill that would allow teachers in the city of St. Louis to leave the traditional tenure track and qualify for performance-based pay.

The measure, sponsored by Sen. Jane Cunningham, R-Chesterfield, and supported by St. Louis Democrat Jeff Smith, would use money from gambling proceeds to create a pool of up to $5 million to pay teachers who qualify based on their performance to earn more each year than their colleagues who stick with the tenure system.

Cunningham’s amendment passed on a voice vote and was attached to the omnibus education bill that passed the Senate at 2:30 this morning after about 8 hours of debate.

The underlying bill altered the foundation formula to accept the additional gambling proceeds expected to flow into education because of the ballot measure passed in November that erased loss limits in Missouri casinos.

But the most contentious debate was on Cunningham’s measure, and other amendments that had to do with making changes to the traditional public school model.

Cunningham’s amendment was vehemently opposed by pro-teachers-union Democrats in the Senate, led by Sen. Joan Bray of University City and Rita Days of St. Louis. But neither Bray or Days were in the chamber when Cunningham’s measure came up for debate and it passed quietly. But Cunningham had drafted the measure incorrectly, so Senate president pro tem Charlie Shields called senators back into the chamber to rescind the amendment, fix it, and then try to pass it again.

By that time, Bray was engaged, and in about an hour long debate, she blasted fellow Democrat Smith for his support of the measure. Smith pointed to merit based pay systems in Chicago and New York and Denver that he said were successful.

“I want to try to provide tools that will help my district succeed,” Smith said.

The bill passed easily on a voice vote.

Senators defeated a measure that would have allowed school districts to go to a 4-day school week in a debate that pitted rural lawmakers vs. urban ones. And after a long debate, senators dropped a measure that would have brought open enrollment to Missouri, and instead decided to study it and have a committee issue a report on open enrollment by the end of the year.