the region, with the French trading another West African holding for the Gambia, but the exchange was never completed. Although the areas were ruled by separate, competing powers, they did not determine an official border between the French and British Senegambian colonies until 1889. At the time, France agreed to accept the current border between the two countries and remove its border trading posts. This decision resulted in the future Senegal (which gained its independence from France in 1960) and the Gambia (which gained independence from Britain in 1965) sharing a large problem: how to successfully maintain two separate countries in a region with shared yet diverse cultural values, and one nation virtually surrounded by another. Prelude of the confederation For each country, the "lock and key" border situation has posed unique problems for international relations, especially in trade and control of regions surrounding the Senegal–Gambia border. Since the end of colonization, the Senegalese government had maintained trade barriers that provided preferential treatment for French goods imported into the country, while the Gambia had virtually no trade barriers. The opposing trade policies fueled a large black market around the Senegal–Gambia border, which brought cheaper manufactured goods into Senegal. The black market also attracted an export drain into the Gambia. The Senegalese government began to institute a delayed payment system with its groundnut (peanut) farms. When farmers sold their harvest to the Senegalese government, they would get a voucher, known as a chit, which they could turn into cash after a three-month waiting period. Not wanting to wait for the Senegalese marketing system to pay them, more farmers began to smuggle their goods to Banjul, where the Gambian government paid in cash. An even greater issue for both countries was the ease with which violence could spread through the region. With shared ethnic communities on both sides of the border, a successful coup in one country could lead to a group of sympathizers in the other, bringing danger to the democratic regimes of both countries. This fear was realized during the 1981 coup attempt to oust President Dawda Jawara of the Gambia. Though the coup attempt was not well organized and quickly fell apart, it resulted in a prolonged period of instability and violence in the Gambia, as the rebels released many criminals from prisons and armed them in hopes that they would support the uprising. Per an existing defense agreement,