Pity the public school teacher. Over the decades their general reputation has gone from valiant servant to ingrate on the public dole. Though they've picked up the added duties of social worker and de facto parent, their schools continue to fail. Someone must take the blame. Dump it on the teachers. So you approach with a certain empathy when Nashville union chief Erick Huth argues against merit pay. The acknowledged proof of skill -- scores on proficiency tests -- is so ridden with variables as
