DENVER (AP) — Colorado is changing the rules for how teachers earn and keep the sweeping job protections known as tenure, linking student performance to job security despite outcry from teacher unions that have steadfastly defended the system for decades.

Many education reform advocates consider tenure to be one of the biggest obstacles to improving America's schools because it makes removing mediocre or even incompetent teachers difficult.

Colorado's legislature changed tenure rules despite opposition from the state's largest teacher's union, a longtime ally of majority Democrats. Gov. Bill Ritter, also a Democrat, signed the bill into law last month.

It requires teachers to be evaluated annually, with at least half of their rating based on whether their students progressed during the school year. Beginning teachers will have to show they've boosted student achievement for three straight years to earn tenure.

Teachers could lose tenure if their students don't show progress for two consecutive years. Under the old system, teachers simply had to work for three years to gain tenure, the typical wait around the country.

After the bill survived a filibuster attempt and passed a key House vote, Democratic Rep. Nancy Todd, a 25-year teacher who opposed the measure, broke into tears.

"I don't question your motives," an emotional Todd said to the bill's proponents. "But I do want you to hear my heart because my heart is speaking for over 40,000 teachers in the state of Colorado who have been given the message that it is all up to them."

While other states have tried to modify tenure, Colorado's law was the boldest education reform in recent memory, according to Kate Walsh, the president of the Washington-based National Council on Teacher Quality, which promotes changing the way teachers are recruited and retained, including holding tenured teachers accountable with annual reviews.

Walsh thinks Colorado is now at the head of the pack in the second round of the Obama administration's Race to the Top competition, a $4.35 billion pot of stimulus money designed to prod just such changes.

"If I was a betting woman, I would absolutely put Colorado in first place," she said.

Teachers won't be at risk of losing tenure until 2015 because lawmakers slowed down the process under political pressure from the teachers' union. Teachers can appeal dismissal all the way to the state Supreme Court, and school districts have the burden of proving why they should be terminated.

Every state but Wisconsin has some form of tenure. The protections were intended to protect teachers from being fired because of their politics, religion or other arbitrary reasons. But Patrick McGuinn, a political science professor at Drew University who has studied tenure, said they have evolved into virtual employment guarantees.

On average, school districts across the country dismiss 2.1 percent of teachers annually, generally for bad conduct rather than performance.

Colorado's measure is a tribute to the tenacity of freshman Democratic state Sen. Michael Johnston, a former Teach for America teacher, principal and Obama education adviser.

The 35-year-old Harvard- and Yale-trained lawyer was appointed to represent a largely minority Denver district that has seen an influx of more white residents because of redevelopment of the city's former airport. He successfully fought changes to the bill that would have eased expectations for teachers with traditionally low performing students.

"What we're saying is that it matters that every one of those kids will get across the finish line," Johnston said.

Although various states have responded to the lure of federal money by moving to tie teacher evaluations to student performance, no other state specifically changed its tenure laws as Colorado did.

In Louisiana, GOP Gov. Bobby Jindal signed a bill partially grading teachers on student test scores in up to 27 school districts. Tenured teachers would face a revocation of tenure hearing if they repeatedly fail under the law, which was opposed by teachers unions.

A push to eliminate tenure for all new teachers and make it easier to fire teachers in Florida passed the Legislature this year but was vetoed by Republican Gov. Charlie Crist, who is now running for the U.S. Senate as an independent.

Past efforts to change tenure have caused problems for both parties.

In Georgia, Democratic Gov. Roy Barnes lost the support of the teachers' union — and later his office — after pushing to get rid of tenure for new hires in 2000.

California Gov. Arnold Schwarzenegger tangled with teachers and lost after calling a special election to change tenure rules in 2005. The teachers' union raised dues and amassed $50 million to fight the proposal.

Many teachers and some education experts argue that tenure reform is unnecessary.

Margaret Bobb, an earth science teacher at Denver's East High School, said bad teachers are often quietly coached out of their jobs by administrators, avoiding the protracted tenure dismissal process. She contends tenure is still needed to prevent good teachers from being dismissed for running afoul of administrators and to prevent experienced — and more expensive — teachers from being let go by cash-strapped districts.

"Education is not just you and your class. It's not an individual activity. If you're doing your best, it's a system you're a part of," Bobb said.


Associated Press writers Randall Chase in Dover, Del., Melinda Deslatte in Baton Rouge, La. and Erik Schelzig in Nashville, Tenn. contributed to this report.