Assessing the President's Preschool Plan

In his State of the Union address, President Obama called for making preschool available to every child in America. But questions abound: Is universal preschool politically and fiscally feasible—or even educationally necessary? Should we be expending federal resources on universal pre-K or targeting true Kindergarten-readiness programs for the neediest kids? How robust is the evidence of lasting impacts? And what exactly is the president proposing?