Missouri voters delivered a defeat Tuesday night to a ballot measure that would change the state’s constitution to ban teacher tenure and require evaluations be based on student performance.

Even as the results were still pouring in, the Missouri State Teachers Association claimed a defeat of the constitutional amendment that was placed on the ballot after a group backed by St. Louis billionaire Rex Sinquefield collected enough signatures earlier his year.

“Students were the big winners in tonight’s election. Defeating Amendment 3 will ensure that students continue to receive quality instruction, and will not just be a number based upon a standardized test,” said Lisa Funk, president of the MSTA, in a statement.

Teach Great, the group funded by Sinquefield, dropped its support after getting the measure on the ballot citing lack of support from Missouri voters. Despite their decision to back out of the race, teachers groups continued to flood the airwaves with ads urging voters to “protect our local schools” and oppose the measure.