The US Customs and Border Protection (CBP) [previously called the Customs Service] and other agencies have used detection devices for years to detect and intercept illicit nuclear material being shipped across our national borders. Following the horrific terrorist attacks of September 11, 2001, radiation portal monitors were purchased in large numbers and deployed at seaports, airports, and land ports of entry. Everyone was aware that these devices had shortcomings and could not reliably detect shielded nuclear material, but they were the best then available. Companies that constructed such devices promised that they were close to perfecting the next generation of the device, which acquired the name: Advanced Spectroscopic Portal Radiation Detection Monitor or ASP. The ASP was billed as being much better at detecting even moderate levels of radiation, of being able to recognize natural radiation (thus reducing the number of false positives), and of being able to operate in a variety of extreme climatic conditions (allowing, for instance, installation on exposed waterfront piers). The reality is that the engineering challenges have proven to be much more complex than anticipated. While the Department of Homeland Security (DHS) was initially enthusiastic about the ASP, its ardor has waned of late. Congress, too, was anxious to deploy the next generation of detection devices, but now is reluctant to appropriate monies to acquire these very expensive machines. New testing protocols are being developed and engineers keep tweaking the devices, hoping for a breakthrough. For now, though, agencies will continue to employ the old monitoring devices, whose shortcomings are known and to which procedures have been adapted.