Bill Clinton uses a car-racing metaphor to explain the difference between rash and calm decision-making in politics. “The great drivers, when the cars get close, the turns get hairy, they calm down, and they see everything, and they act,” he says. “The ones who are fearful and can't concentrate and can't calm down, run into the wall.” Republican leaders should pay attention, because on the issue of whether Clinton’s sex life is relevant 14 years after he left office, they’re once again careening toward a wall. Sen. Rand Paul dredged up Clinton’s affair with Monica Lewinsky and his subsequent impeachment,...