Erik Prince, the founder and former head of the controversial private security firm Blackwater, is mulling over a run for a U.S. Senate seat in Wyoming. The potential move has been encouraged by former White House chief strategist Steve Bannon, who has sought to wage war on the Republican establishment. Prince, 48, is now the head of the China-based private aviation and logistics firm, Frontier Services Group, and would challenge Sen. John Barrasso, R-Wyo., who is an establishment favorite. Throughout the weekend Prince has looked for ways he could establish residency in the state, the New York Times reported. Barrasso...