Terrorist financing describes a form of financial crime in which an individual or entity solicits, collects, or provides funds "with the intention that these funds] may be used to support terrorist acts or organizations." While terrorists can benefit from big donations of deep-pocketed financiers sympathetic to their cause, terrorist financing often involves relatively small-dollar amounts and itself is just a subset melting into the larger stream of all financial crime occurring in the international financial system. The threat to national security from terrorist financiers is real, so while U.S. policymakers have long recognized the idea that "following the money" through the retail banking system can help combat terrorism and related forms of illicit finance, new financing technologies have arisen since the September 11, 2001, terror attacks that require constant renewal of detection and disruption methods.