The sudden increase in crime and violence in some Mexican cities and regions has raised security concerns not only in Mexico, where President Felipe Calderon categorized these crimes as a threat to Mexican society, but also in the United States, where Department of Homeland Secretary head Janet Napolitano referred to stemming the violence as "vital to core U.S. national interests." Mexico is concerned with the latent threat of violence spreading all over the nation, while the U.S. is trying to guard against spillover. Both governments are concerned by the increased violence and its impact on communities along the U.S.-Mexican border. Because of its geopolitical location along the southern U.S. border, Mexico is susceptible to possible undesired effects of U.S. strategies. These unintended, second-degree consequences are known as "balloon effects," after the airflow inside a balloon when constriction applied to one area sends pressure to another area in the balloon, thinning and weakening its wall. Since 2006, Mexico's strategy for countering transnational organized crime and related activities has sent the balloon effect in two directions: first, inside Mexico, where government actions have unbalanced the criminal structure, creating balloon effects inside Mexican territory; and second, within the U.S. while asking to escalate the Mexican effort to improve its anti-crime strategy with U.S. assistance has escalated conflict and led to a holistic strategy against transnational organized crime and related activities in the Americas.