sentences:  An ongoing issue in the border region was the exact boundary between Mexico and the U.S., particularly because the channel of the Rio Grande shifted at intervals.In 1889, the International Boundary and Water Commission was established, and still functions in the twenty-first century.In 1909, William Howard Taft and Porfirio Díaz planned a summit in El Paso, Texas, and Ciudad Juárez, Mexico, a historic first meeting between a U.S. and a Mexican president, the first time an American president would cross the border into Mexico, and only the second international trip by a sitting president Diaz requested the meeting to show U.S. support for his planned eighth run as president, and Taft agreed to support Diaz in order to protect the several billion dollars of American capital then invested in Mexico.