The Hay-Herrán Treaty, signed (Jan., 1903) with Colombia, would have given the United States a strip of land across the Isthmus of Panama in return for an initial cash payment of $10 million and an annuity of $250,000, but the Colombian senate refused to ratify it. An insurrection, involving Bunau-Varilla and other proponents of the canal as well as the regional population, was encouraged by the United States. Panama rose in revolt on Nov. 3, 1903, declaring itself independent of Colombia. Invoking the treaty of 1846, the United States sent an American warship to Panama, and its presence prevented Colombian troops from quelling the outbreak. The new republic was formally recognized three days later, and on Nov. 17 the Hay–Bunau-Varilla Treaty was signed, granting to the United States, in return for the same terms offered Colombia, exclusive control of a canal zone in perpetuity, other sites necessary for defense, and sanitary control of Panama City and Colón. Colombia's efforts to secure redress for the loss of Panama later resulted in ratification of a treaty (1921) by which the United States paid Colombia $25 million, and Colombia recognized the independence of Panama.