On a personal level, it’s impossible not to feel great sympathy for Joe Biden when he talked about his son Beau, who died of brain cancer in May at age 46. His anguish still visible on Wednesday, as he announced he would not seek the presidency, Biden said he was making a “personal” commitment to seek instead a cure for cancer; as he put it, “I’m going to spend the next 15 months in this office pushing as hard as I can to accomplish this.”