In a victory for teacher unions, a divided California Supreme Court decided Monday to let the state's teacher tenure law stand.

The high court decided 4-3 not to review a lower court ruling that upheld tenure and other job protections for teachers. That ruling came in a lawsuit by a group of students who claimed that incompetent teachers were almost impossible to fire because of tenure laws and that schools in poor neighborhoods were dumping grounds for bad teachers.

The case was closely watched around the country and highlighted tensions between teacher unions, school leaders, lawmakers and well-funded education reform groups over whether policies like tenure and firing teachers with the least seniority keep ineffective instructors in the classroom.

Dozens of states have moved in recent years to get rid of such protections or raise the standards for obtaining them.

Associate Justice Goodwin Liu voted for the California Supreme Court to take up the case, saying it affected millions of students statewide and presented a significant legal issue that the lower court likely got wrong.