Can a teachers' union successfully be both a hardball-playing defender of its rights and a collaborative force for the common good? It is both a question of philosophy and, increasingly, one of policy direction for the American Federation of Teachers (AFT), whose biennial convention in Detroit showed delegates grappling with the tension between…

Gov. Scott Walker's sweeping proposal to scale back collective bargaining rights for most public employees in Wisconsin has sparked a rancorous standoff with teachers across the state--and fueled speculation about whether similar plans will gain traction in other parts of the country. But as massive demonstrations played out in Madison--an…