Officials in Honolulu have granted the developers of a luxury, oceanfront estate tied to Barack Obama a major exemption from environmental laws designed to protect Hawaii’s beaches. The shoreline permit, issued by Honolulu’s Department of Planning and Permitting on Monday, clears the way for the controversial multimillion dollar renovation of a century-old seawall in the heavily Native Hawaiian community of Waimanalo. Under state and county laws, such projects are typically banned. Scientists and environmental experts say seawalls are the primary cause of beach loss throughout the state, and officials expect older ones to fall into obsolescence. But the property owners,...