HOWARD ROSENTHAL, a professor whose research shed light on political ideologies, died July 28 at age 83. Rosenthal was on the Princeton faculty from 1993 to 2005, when he transferred to emeritus status. He also taught at Carnegie Mellon University and New York University. With collaborator Keith Poole, Rosenthal developed statistical tools to analyze how senators and representatives voted on various pieces of legislation, a project that led to a long-term interest in political polarization. Rosenthal, Poole, and Princeton professor Nolan McCarty co-wrote the 2006 book Polarized America: The Dance of Ideology and Unequal Riches.