The fourth-generation heir to the Bush political dynasty, groomed for office since his childhood, is coming of age and building a political network. His great-grandfather was a senator, his grandfather and uncle presidents, his father governor of Florida. Now a new George Bush is contemplating going into the family business. George Prescott Garnica Bush, known to friends as "P," is not just a chip off the old preppy block. The 36-year-old son of Jeb Bush and nephew of W. is Hispanic -- his mother, Columba, is from Mexico -- with brown skin, thick black hair, and a toothy, gleaming smile....