“When I was in another State they would slip and say ‘now I want to introduce the Senator from DuPont–I mean Delaware’”, Joe Biden had joked at a Senate Subcommittee on Crime session. There’s a certain truth to the joke. DuPont is the corporation that defines Biden’s career. His first Senate bid was staffed with DuPont employees, including future chief-of-staff and senator Ted Kaufman, who was conveniently allowed to take a “leave of absence” from DuPont to help elect Biden. Biden celebrated his victory at the Hotel DuPont and bought a former DuPont mansion. DuPont figures in a lot of...