Despite the denials, South Africa’s banks have had enough. In recent weeks, all four of the biggest banks have severed their links to the Guptas, closing the bank accounts of the Gupta holding company, Oakbay Investments. The Guptas were furious. In newspaper advertisements, they said the banks were jeopardizing the livelihoods of 7,500 of Oakbay’s “employees and dependents.” The Zuma government swiftly responded by delegating three cabinet ministers to meet with the banks to settle the matter. It was an extraordinary state intervention in a private business dispute. And, critics said, it was further proof of the remarkable power of...