Jack returned to the United States after his health forced him to leave the South Pacific, but Joe Jr. remained in Europe, where he was serving as a navy pilot. On August 12, 1944, Joe Jr.'s plane exploded, killing him. Joe's death was devastating for the entire Kennedy family, and Jack found that he had to rediscover his purpose. Up to that point in his life, the competition with his brother had been a guiding force, and without an opponent Jack was unsure about his future. However, his father determined that he would take his brother's place and embark upon a political career. With his family's support, Jack ran for Congress.