sentences:  During Díaz's long presidency, Mexico was opened to foreign investment and U.S. entrepreneurs invested in ranching and agricultural enterprises and mining.The U.S. played an important role in the course of the Mexican Revolution (1910–20) with direct actions of the U.S. government in supporting or repudiating the support of revolutionary factions.The long border between the two countries means that peace and security in that region are important to the U.S.'s national security and international trade.