The United Stated had exercised control over the region of the Panama Canal since 1903, when the Hay–Bunau-Varilla Treaty granted rights to the United States to build and control the Panama Canal Zone. In 1977, after years of negotiation between the United Stated and Panama, US President Jimmy Carter and Panamanian leader Omar Torrijos signed the Panama Canal Treaty; according to the terms of the treaty, the United States would transfer control of the Panama Canal to the Panamanians by the year 2000.