Leading up to Duncan's nomination, a divide grew between Democratic camps.
One side wants to continue the push for accountability via standardized testing – applying it not just to schools but also to individual teachers. It wanted the Education secretary post to go to someone like Joel Klein or Michelle Rhee, who have butted heads with teachers unions as the heads of New York City's and District of Columbia's schools, respectively.
The other side – with which teachers unions are more typically aligned – argues that student achievement gains depend on bringing greater resources to schools and addressing poverty beyond school walls because of its impact on children's health and learning. The resource-focused proponents rallied more around Stanford scholar Linda Darling-Hammond, who led Mr. Obama's education transition team.