It should be noted that not only Texas but also California, New Mexico, and large portions of Arizona were once parts of Mexico. The Mexican war mentioned above broke out largely when Mexico spurned President James Polk's attempts to buy California. Mexican influence is quite apparent in these areas in place names, architecture, etc. It should also be noted that the U.S. came very close to war with Mexico during Woodrow Wilson's Presidency. Wilson interfered actively in Mexican politics which caused tremendous resentment south of the border. Also, during that time, Pancho Villa invaded the mainland U.S. in response to which Wilson sent Gen. John J. Pershing into Mexico in a ultimately failed attempt to capture him. When Wilson ran for re-election in 1918, his slogan was "He Kept Us Out of War." Many assume this was World War I, since the U.S. was not yet engaged. Actually, it meant that he had avoided war with Mexico.