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. Both sides agreed that the disputed Chamizal strip connecting El Paso to Ciudad Juárez would be considered neutral territory with no flags present during the summit, but the meeting focused attention on this territory and resulted in assassination threats and other serious security concerns. The Texas Rangers, 4,000 U.S. and Mexican troops, U.S. Secret Service agents, BOI agents (later FBI) and U.S. marshals were all called in to provide security. An additional 250 private security detail led by Frederick Russell Burnham, the celebrated scout, was hired by John Hays Hammond, a close friend of Taft from Yale and a former candidate for U.S. vice president in 1908 who, along with his business partner Burnham, held considerable mining interests in Mexico. On October 16, the day of the summit, Burnham and Private C.R. Moore, a Texas Ranger, discovered a man holding a concealed palm pistol standing at the El Paso Chamber of Commerce building along the procession route. Burnham and Moore captured and disarmed the assassin within only a few feet of Taft and Díaz. The Mexican Revolution The United States had long recognized the government of Porfirio Díaz, once the U.S. recognized his government since he had first come to power by coup. As Díaz approached eighty years old, he gave an interview to a journalist working for a U.S. publication, saying he was not going to run in the scheduled 1910 elections. This set off a flurry of political activity in Mexico about presidential succession. For the U.S., it wanted the new president to continue Díaz's policies that had been favorable to U.S. business interests and produced stability domestically and internationally. Díaz reneged on his promise not to run, exiled the most viable candidate to continue his policies, General Bernardo Reyes and had the most popular opposition candidate, Francisco I. Madero jailed. After the November elections, political unrest in Mexico became open rebellion in Morelos and in northern Mexico. The Mexican Federal Army was unequal to the challenges