In 1909, Díaz and William Howard Taft, the then president of the United States, planned a summit in El Paso, Texas, and Ciudad Juárez, Chihuahua, Mexico, a historic first meeting between a U.S. president and a Mexican president and also the first time an American president would cross the border into Mexico. Díaz requested the meeting to show U.S. support for his planned seventh run as president, and Taft agreed to protect the several billion dollars of American capital then invested in Mexico. After nearly 30 years with Díaz in power, U.S. businesses controlled "nearly 90 percent of Mexico's mineral resources, its national railroad, its oil industry and, increasingly, its land." 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, FBI agents and U.S. marshals were all called in to provide security. An additional 250-man private security detail led by Frederick Russell Burnham, the celebrated scout, were 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 16 October, 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 Díaz and Taft.