"Much has been written in the aftermath of September 11 on the porosity of America's borders and the failure of various agencies to share, fuse, analyze, and exploit available information to stop foreign threats before they enter the country. The resources and methods available to U.S. border control agencies appear to be no match for the myriad threats that could arrive from outside the country. Asymmetrical military and terrorist threats have a natural gateway into America via the marine transportation system. In the uncertainty following the September attacks, the immediate response of security services around the country-the Coast Guard included-was to shut down the systems under their control until measures were taken to ensure that additional attacks were not already in progress. These system stoppages were generally short-lived because the economic impacts were intolerable, not only in dollar costs but also in potential loss of access to the essentials of daily American life. The United States is a trading nation, both domestically and globally, and relatively unimpeded movement of goods and people is necessary for its economy to function. Given the importance of international goods and materials to the American economy, closing our borders for more than a short period is infeasible. Furthermore, with our growing reliance on just-in-time delivery of foreign goods, even slowing the flow long enough to inspect either all or a statistically significant random selection of imports would be economically intolerable. This notion-exploiting available information to discern threats and concentrate resources to stop them-is at the heart of the maritime domain awareness (MDA) concept."
Defense Horizons No. 7
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/