Within a month of the nationalist victory, Cabral, whose troops were the first to enter Santo Domingo, ousted Pimentel, but a few weeks later General Guillermo led a rebellion in support of Báez, forcing Cabral to resign and allowing Báez to retake the presidency in October. Báez was overthrown by the Cibao farmers under Luperón, leader of the Partido Azul, the following spring, but Luperón's allies turned on each other and Cabral reinstalled himself as president in a coup in 1867. After bringing several "Azules" ("Blues") into his cabinet the "Rojos" ("Reds") revolted, returning Báez to power. In 1869, Báez negotiated a treaty of annexation with the United States. Supported by U.S. Secretary of State William Seward, who hoped to establish a Navy base at Samaná, in 1871 the treaty was defeated in the United States Senate through the efforts of abolitionist Senator Charles Sumner.