Responding to criticism that tenure gives even poor teachers a job for life, Randi Weingarten, the president of the American Federation of Teachers, announced a plan Thursday to overhaul how teachers are evaluated and dismissed, reports the New York Times. It would give tenured teachers who are rated unsatisfactory by their principals a maximum of one school year to improve. If they did not, they could be fired within 100 days. Teacher evaluations, long an obscure detail in an educator’s career, have moved front and center as school systems try to identify which teachers are best at improving student achievement, and to remove ineffective ones…