Nearly four times as many Sunni Islamic militants are operating around the world today as on Sept. 11, 2001, despite nearly two decades of American-led campaigns to combat Al Qaeda and the Islamic State, a new independent study concludes. That amounts to as many as 230,000 Salafi jihadist fighters in nearly 70 countries, with the largest numbers in Syria, Afghanistan and Pakistan, according to the study by the Center for Strategic and International Studies, a Washington think tank. The report's conclusions ... underscore the resiliency of these terrorist groups, and the policy failures by the United States and its allies in responding. The findings also highlight the continuing potency of the groups' ideology and social-media branding in raising money and attracting new recruits as they pivot from battlefield defeats in strongholds like Iraq and Syria to direct guerrilla-style attacks there and in other hot spots. The West has largely failed to address the root causes of terrorism that perpetuate seemingly endless waves of fighters who are increasingly turning to armed drones, artificial intelligence and encrypted communications to foil the allies' conventional military superiority, the report said. Last week, Brown University's Watson Institute for International and Public Affairs released its annual report, the Costs of War study, in which it calculated that the United States will have spent $5.9 trillion on activities related to the global counterterrorism campaign by October 2019.