Not many people think about the US casino industry on a regular basis. In Frank Fahrenkopf’s D.C. corner office, which is located a block off Pennsylvania Avenue, are the custom desk from London he had crafted 24 years ago, an American flag standing in the corner and a knickknack of herding elephants signifying the job he once held as chairman of the Republican National Committee. The wall of framed photos with political heavyweights from Ronald Reagan and Margaret Thatcher to Barack Obama — reputedly one of the more impressive collections in town accumulated over 30 years — has been taken…