A secret business deal between the government of Guinea and a multinational firm with a U.S. partner aided by the Obama administration’s wrongheaded foreign policy could cost American businesses billions. Congress ought to investigate to protect American investors, expose any political shenanigans and prosecute the guilty. The London Sunday Times first cracked the story June 3 of the secret $25 million loan between an offshore company, Palladino Capital 2, and the cash-strapped West African country. The funds, according to the loan agreement, were to finance the start-up of Guinea’s state mining company, Heritage, but the cash allegedly disappeared and the...