The Chamizal dispute between Mexico and the United States was a boundary conflict over about 600 acres at El Paso, Texas, between the bed of the Rio Grande as surveyed in 1852 and the present channel of the river. About 100 acres of the tract fell within the business district of the city. The dispute was based on the interpretation of the Treaty of Guadalupe Hidalgo of 1848 and the Treaty of 1884. These agreements specified that the boundary should be down the middle of the river along the deepest channel, regardless of any alterations in the banks or channels. The Treaty of 1884 also provided that the alterations had to result from such gradual natural causes as the erosion of alluvium and not from the cutting off of land by floods or sudden changes in the river's course. This provision followed the long-established doctrine of international law that when changes in the course of a boundary river are caused by a deposit of alluvium, the boundary changes with the river, but when changes are due to avulsion, the old channel remains the boundary.
The river continually shifted south between 1852 and 1868, with the most radical shift in the river occurring after a flood in 1864. By 1873 the river had moved approximately 600 acres, cutting off land that was in effect made United States territory. Eventually the land was settled and incorporated as part of El Paso. The controversy started in 1895, when Mexico made a claim for the putative owner of the land, Pedro I. García, whose title dated to 1827.
In 1910, in an effort to determine proper title to the land, Mexico and the United States agreed on rules of arbitration. A third member, a Canadian, was added to the International Boundary Commission (later the International Boundary and Water Commission) to complete the task. The tribunal was to decide whether or not the change in the river's course had been gradual, whether or not the boundaries set by treaties in 1848 and 1853 were fixed, and whether or not the 1884 treaty applied. Mexico claimed that the boundary had never changed and therefore that the Chamizal was technically Mexican territory, while the United States claimed that the 1884 convention applied, that the boundary was the result of gradual erosion, and that the property therefore belonged to the United States.
The commission met on June 10, 1911, in El Paso. According to its proposed settlement, the part of the disputed tract lying between the riverbed, as surveyed in 1852, and the middle of the river in 1864 was declared United States territory; the remainder of the tract was declared part of Mexico. Since this decision divided the Chamizal (Spanish for "Chamiza Thicket") between the two countries, the United States considered that the proposal did not conform to the terms of the arbitration and refused to accept it. Mexicans regarded the American refusal to accept the verdict as evidence of unwillingness to negotiate in good faith on matters that did not meet United States interests.
Between 1911 and 1963 several more initiatives were undertaken by different presidential administrations to solve the Chamizal debate. One suggested compromise was that the United States would forgive Mexico's default on the Pious Fund of the Californias, which was intended for the perpetual support of missions and spread of Christianity in California, in exchange for El Chamizal. Other proposed compromises included exchange of other territory along the Rio Grande for the Chamizal, direct purchase of the tract, and inclusion of the Chamizal in the Rio Grande Rectification Project.
The entire tract was under the jurisdiction of the United States and the state of Texas. No suits for delinquent taxes were contested, on the grounds that the property was in disputed territory and therefore not subject to taxation. In fact, aside from the question of guaranteed titles to the land in the tract, no distinction was made between it and the rest of El Paso. The dispute continued to affect Mexico-United States relations adversely until President John F. Kennedy agreed to settle it on the basis of the 1911 arbitration award. It was hoped that settlement of the dispute would strengthen the "Alliance for Progress" and solidify the Organization of American States.
The dispute was formally settled on January 14, 1963, when the United States and Mexico ratified a treaty that generally followed the 1911 arbitration recommendations. The agreement awarded to Mexico 366 acres of the Chamizal area and seventy-one acres east of the adjacent Cordova Island. Although no payments were made between the two governments, the United States received compensation from a private Mexican bank for 382 structures included in the transfer. The United States also received 193 acres of Cordova Island from Mexico, and the two nations agreed to share equally in the cost of rechanneling the river. In 1964 President Adolfo López Mateos and President Lyndon B. Johnson met on the border to end the dispute officially. On September 17, 1963, Senator John Sparkman of Alabama introduced in Congress the American-Mexican Chamizal Convention Act of 1964, which finally settled the matter. In October 1967, Johnson met with Mexican president Gustavo Díaz Ordaz on the border and formally proclaimed the settlement. See also BANCOS OF THE RIO GRANDE, and BOUNDARIES.