Kenneth J. Cooper, a senior editor at WGBH News in Boston, has been a journalist for four decades, specializing in government, politics and social policy, at The Washington Post, Boston Globe, Knight Ridder, St. Louis Post-Dispatch and St. Louis American. In 1984, Cooper, then 28, shared a Pulitzer Prize for special local reporting for “The Race Factor,” a Boston Globe series that examined institutional racism in Boston. For decades, he was the youngest African American to win a Pulitzer for journalism. He is co-author with photographer Don West of “Portraits of Purpose: A Tribute to Leadership.”