Trump in unexpected trip to Mexico after harsh criticism

By Dave Graham MEXICO CITY (Reuters) - Donald Trump traveled to Mexico on Wednesday to meet President Enrique Pena Nieto in an unexpected trip to a country which the Republican presidential candidate has frequently vilified as the main source of illegal immigration and drug smuggling to the United States. Trump's visit to Mexico City took place hours before he was due to deliver a highly anticipated speech in the border state of Arizona on how he would tackle illegal immigration if he wins the N