President <PERSON> (standing at right) joined <PERSON>, principal of the Hennigan Elementary School in Jamaica Plain on Tuesday as part of Boston's ``Principal for a Day.'' <PERSON> shadowed Cordon (seated at left) on the principal's daily routine of morning announcements and classroom visits, and spoke to a fourth-grade class about the Civil War. The program, run by Boston Plan for Excellence in the Public Schools, brings business, civic, and educational leaders into the Boston public schools with the goal of inspiring partnerships with the schools. Harvard partners with the <PERSON> in the areas of leadership and professional development, family engagement, after-school academic support, and science mentoring.