 Prior to the reunification of Yemen in 1990, Shamlan was the Minister of Infrastructure and Oil in the socialist government of South Yemen.He was the recognized presidential candidate of the Yemeni opposition coalition, a coalition which consists of the Islamist Islah, the Yemen Socialist Party and several smaller parties, in the 2006 presidential election, but was defeated by incumbent president Ali Abdullah Saleh.Originally from Hadhramaut, Shamlan was educated in the elite Ghayl ba-Wazeer School [ġail bā wazīr], which was one of the best schools in Yemen and beyond at the time.