The terrorist threat against the Brooklyn Bridge and the Statue of Liberty, however vague it might have been, is a reminder that America's ports and harbors are a major point -- perhaps the major point -- of vulnerability. Indeed, after the upgrade in security at airports since September 11, terrorists may view airliners as "hard" targets. But America's seaports, all 361 of them, are basically as "soft" as ever.

Some six million containers -- typical size, 40'x8'x8' -- come into the United States by water every year. At most, three percent of those containers are inspected, according to the US Customs Service. And when they are, interesting things are sometimes found. On February 9, a French cargo ship, La Tour, arrived in the Port of New York. Its paperwork indicated it was carrying "explosives." The US Coast Guard boarded the vessel and noticed that one of the 2000 containers was above deck, right where the crew, or anyone else, could get at it. When the boarding party asked if there was anything special about that container, the crew chorused back, "No, everything is OK."

But then an alert Coast Guard officer noticed that the seal on the container had a serial number conflicting with the container's shipping papers. At this point, the boarding part demanded a look-see.

The inspectors found not just explosives, but 47 nuclear warheads, all the detonators and wiring ready to go, lacking only the nuclear fissile material that would make them all mushroom-cloud capable. After three days, the Coast Guard was able to verify that the warheads belonged to the US Army, having been legitimately shipped to a Raytheon Corporation facility in Kiel, Germany, and back, for routine maintenance. And so the freighter and its crew -- guilty of nothing more, apparently, than sloppy paperwork--were allowed to proceed to dockside.

This incident, first reported in Lloyd's List, a maritime trade publication, and subsequently confirmed by the Coast Guard, nonetheless raises questions and concerns. The ship La Tour, for example, was constructed in China just last year. Could any sort of terrorist device have been built into its works? One of its prior ports of call was Hamburg--the longtime domicile of the late Mohammed Atta, the 9-11 ringleader. Could anyone of his ilk have stowed away from that city, home to a huge transient Muslim population? And the warhead-containing container was sitting exposed above deck. Why was that? Could any of the crew have been fiddling with it? The master of the ship was a Yemeni national; Yemen, of course, has been a focus of concern since terrorists detonated a bomb next to the destroyer USS Cole in Aden Harbor in October 2000.

Meanwhile, other troubling straws rustle in the wind. Last week the Fox News Channel reported that since March, some 25 Middle Eastern men have smuggled themselves into the country in shipping containers through four ports: Long Beach, Ca., Miami, Port Everglades, Fl., and Savannah, Ga. Appearing on CNN later, Sen. Bob Graham (D-Fl.) worried that the mystery men, be they terrorists, tourists, or job seekers, have since been "lost in the American population." Interestingly, Graham, the chairman of the Senate Intelligence Committee, heard about the incident from the news media. He then had to call the "Intel Community" to find out what was going on.

Paul Anderson, communications director for Graham, was asked to comment on this sequence of events. Isn't it a little strange that one of the leaders of the 9-11 investigation, not to mention the elected representative of the state with two of the compromised ports, had to learn of these squirrely incidents from reporters? "No, it's often the case," Anderson replied.

Journalists and pundits are frequently taken to task for "Monday morning quarterbacking." Yet nobody foresaw exactly what would happen on 9-11; the real breakdown intelligence failure was Atta & Company's failure to 'fess up in advance. But oftentimes, the general outlines of the future are often predictable. It seems plain enough, for example, that America’s enemies have come up with plenty of motive, however twisted, for attacking the United States. And they have plenty of means -- America’s soft-target ports being perhaps the most obvious.

So here’s some "Saturday evening kibitzing": an attack on, or through, America’s ports is coming -- unless, of course, it’s already here.