The U.S. State Department has expanded its travel advisory for Mexico with a new nationwide warning: terrorism. The label, previously limited to certain states, now applies to the entire country. Officials say cartel groups and other criminal organizations are using tactics that resemble insurgency operations, with violence sometimes hitting tourist areas. The change could have far-reaching consequences for tourism, business travel, and public perception. What does this classification really mean, and why did Washington decide to act now . . .