NASHVILLE, Tenn. (AP) -- Republican Gov. Bill Haslam on Tuesday signed into law a measure to make it more difficult for teachers to obtain and keep tenure in Tennessee. It came shortly after a key House panel advanced another of his initiatives that would lift a cap on the number of charter schools in the state.

The new law will allow teachers to qualify for tenure after five years on the job, longer than the current three. It will also provide a mechanism for teachers to lose tenure if they perform poorly in consecutive years.

"I think, quite frankly, three years was too short a time to grant something with such a great privilege like tenure," he said. "I think the bar had been set too low."

Critics say an evaluation system to be used to make tenure decisions isn't in effect yet and that it has not been determined how best to rate educators whose subjects aren't covered by the state's value-added test scoring program.

Amendments to delay the proposal at least a year failed.

"I think this is too important to keep pushing off until we get it perfect," Haslam said. "We've got an evaluation committee that's worked hard to get the process and will continue to evaluate."

Haslam also reiterated that the legislation is not intended to undermine teachers but help enhance their performance.

"Several folks have said ... this is about pointing fingers at teachers," he said. "Nothing could be further from the truth. Great teachers are exactly what we need in the classroom."