"Minimize does not mean eliminate," he said.
The department's maritime security strategy, released prior to the Mumbai attacks, paints a grim picture of US port vulnerabilities. Officials believe a Mumbai-style attack is plausible.
"The exploitation of a small vessel to provide a standoff attack platform provides numerous benefits for terrorists," says the report. "The use of a small vessel as a standoff weapon platform provides greater operational security, improved access to targets, and a ready means of escape."
Creating a viable maritime security strategy may be difficult politically. But if protecting the country on 9/11 was a "failure of imagination," then a revision of the security approach to the nation's coastline is necessary, says Allen. But the road ahead is far from straightforward.
"The problem is so broad and immense and complex that it's kind of hard to reduce it to a couple of simple equations and say 'this is where we need to go,'" he says.
(c) Copyright 2009. The Christian Science Monitor