Detecting radioactive materials at U.S. ports remains a big challenge for federal officials.

During the 2008 presidential campaign, Barack Obama promised to "develop technology that can detect radiation and determine the danger it poses, and he will work with the maritime transportation industry to integrate this technology into their operations so as to maximize security without causing economic disruption."

As we noted in our previous update, the Department of Homeland Security's Domestic Nuclear Detection Office spent years testing a new technology, the Advanced Spectroscopic Portal system, that was intended to improve the detection of threats while decreasing the number of false positives. The new system was designed to supplant radiation monitors currently used by Customs and Border Protection at ports of entry, as well as the handheld devices used today for secondary screening.

However, this next-generation system ran into technical difficulties and cost overruns.. In 2012, the Government Accountability Office reported that once testing became more rigorous, the machines "did not perform well enough to warrant deployment." As a result, DHS canceled the program in July 2012.

This failure only heightened the ongoing challenges the government was facing in fulfilling the requirement to scan 100 percent of all U.S.-bound cargo containers before they are placed on a vessel at a foreign port. This requirement was approved by Congress and signed by President George W. Bush as part of the Implementing Recommendations of the 9/11 Commission Act of 2007.

The Secure Freight Initiative -- a pilot project aimed at testing the feasibility of 100 percent scanning -- has run into trouble. Customs and Border Protection implemented the initiative at six ports, but according to GAO, "logistical, technological, and other challenges prevented the participating ports from achieving 100 percent scanning," which led officials to reduce the program's scope to just one port.

Meanwhile, another program known as the Megaports Initiative, is facing severe funding cuts. Through August 2012, the federal government had spent $850 million on 42 projects in 31 countries, which is short of the 100 projects initially envisioned. The projects include equipping seaports with radiation detection equipment, training foreign inspectors and helping foreign governments operate and maintain the equipment. But the administration;s fiscal year 2013 budget proposes an 85 percent cut as well as a shift from establishing new ports to sustaining existing ones.

"Without a long-term plan for ensuring countries" ability to continue Megaports operations, (the federal government) cannot be assured that its $850 million investment will be sustained," GAO concluded. GAO also criticized a lack of coordination between Megaports and other, overlapping security initiatives.

This long list of challenges led Homeland Security Secretary Janet Napolitano to extend the deadline for 100 percent scanning by two years, to July 2014. But experts say that making even the delayed implementation schedule a reality is a longshot.

"The Obama administration has essentially maintained the inspection protocol developed under the Bush Administration of relying on a targeting algorithm to select a tiny percentage of containers for inspection by non-intrusive technology," said Stephen Flynn, the founding co-director of the George J. Kostas Research Institute for Homeland Security at Northeastern University.

How much cargo goes unscanned? The "vast majority -- over 95 percent," Kevin McAleenan, the acting assistant commissioner for the Customs and Border Protection office of field operations, testified before the House Homeland Security Border and Maritime Security Subcommittee on Feb. 7, 2012.

In fact, even though Customs and Border Protection currently has inspectors in 58 overseas ports for the stated purpose of collaborating with foreign officials, the U.S. is only inspecting about 2 containers per day in each of those ports, according to Flynn's calculations. For most cargo shipments, "as far as assurance of what we know in there, we have the manifests and the manifests only," said GAO's Stephen L. Caldwell at the House hearing.

Such a small inspection rate "does not represent much of a deterrent for preventing illicit activity within global supply chains," Flynn said. He added that the U.S. failure to inspect cargo overseas means that the only other option for inspecting cargo deemed suspicious is to scrutinize it at ports in the middle of highly populated U.S. cities with lots of critical infrastructure nearby.

The establishment of a 100 percent scanning goal in 2007 may have been unrealistic, but the federal government hasn"t even met more modest thresholds. The effort to beef up port security against bomb-ready radioactive materials has been beset by myriad challenges. We rate it a Promise Broken.