Libya’s ability to reclaim its role as a reliable supplier of crude depends on the fate of a pair of oil ports on the war-ravaged country’s coast. Es Sider and Ras Lanuf have changed hands twice this month as rival military groups have battled over them. The two ports hold almost half of Libya’s capacity to export oil from onshore terminals, and the country’s ability to sell abroad affects prices globally.

1. Why are the ports so important?

Libya’s oil ports have been a focus of competing political forces since central authority collapsed after the 2011 ouster and killing of strongman Muammar Qaddafi. Es Sider and Ras Lanuf are especially valuable because they are the main outlets for crude pumped at fields in Libya’s interior. When operating normally, Es Sider can export as much as 340,000 barrels a day, while Ras Lanuf can ship 220,000 barrels a day. Located in Libya’s so-called Oil Crescent along its central Mediterranean coast, the terminals together account for 47 percent of the total capacity of the country’s onshore oil ports. Whoever controls them has a grip on Libya’s most important source of income.