A leading historian argues that Johnny Cash was the most important political artist of his time Johnny Cash was an American icon, known for his level, bass-baritone voice and somber demeanor, and for huge hits like "Ring of Fire" and "I Walk the Line." But he was also the most prominent political artist in the United States, even if he wasn't recognized for it in his own lifetime, or since his death in 2003. Then and now, people...