While appealing to President Trump’s penchant for drama and a year-long Republican drumbeat, designating Mexican drug trafficking organizations (DTOs) as terrorist groups will not bring any benefits or tools to U.S. policy. The designation of DTOs under the U.S. Kingpin Act already provides the United States with the same and complete tool box—including wiretapping, steep penalties, financial intelligence, asset seizures and money laundering charges—against any individuals associated with the groups. The United States can already deny visas to individuals collaborating with DTOs and can cut off their access to the U.S. financial system. Designating them terrorist organizations will counterproductively constrict and limit U.S. policy options. It would mandate that U.S. officials and other entities operating in Mexico guarantee that none of their money and resources reach terrorist groups. So, if the designation goes through, the United States may, for example, be self-deterred from delivering alternative livelihood programs in Guerrero if a terrorist-designated DTO could usurp some of the money. In Colombia, even after the peace deal, the United States cannot provide any assistance to any program in which ex-FARC members participate. In Nigeria, the United States needs to go through extraordinary legal contrivances to deliver assistance to a program for low-level Boko Haram defectors, even children who have been dragged into Boko Haram slavery. Worse yet, the United States can impose severe sanctions against countries and NGOs that deliver aid that could trickle to a terrorist group. This threat gravely increased the deaths of Somalis during the 2011 famine as international NGOs were scared off. In fact, U.S. and international sanctions against material support to terrorist groups have criminalized humanitarian aid. The Obama administration contemplated designating the Zetas as a terrorist group and wisely backed away from doing so. President Trump’s policy guideline does the opposite of what President Obama intended. Hopefully, U.S. professional foreign service officers and civil servants will manage to persuade Trump to refrain from applying the designation despite his inclinations.