America's 'ferry tale' of security

THERE IS A small island about 10 miles off the coast of Maine serviced by a 19-car ferry from the mainland. The year-round population is about 350, although with July in full flower, the island's numbers are swelling with summer people.

On the island, where the ferry docks, there is a small ticket office in which a couple of capable and friendly women, who know most everybody coming on and off the ferry, take turns selling tickets.

Since 9/11 an observation system has been installed, costing I don't know how many thousands of dollars. There is a surveillance camera mounted outside so that if a ticket taker wants to observe the goings on in the ferry parking lot and the ferry ramp itself, all she has to do is turn to her left and see it all in living color on a television screen. If she looks over her right shoulder she can see exactly the same scene out the window.

Now, it is easy to find some silliness in our post-9/11 efforts to plug the rat holes in our national transportation system safety. Transportation by its very nature is always vulnerable to terrorist attack. And I think we can be a little tolerant in a nation's desperate efforts after the most devastating attack ever on American soil.

Nor would I quarrel with the need to worry about the nation's ferry services. According to the Coast Guard, more than 135 million people travel by ferry every year, and an attack on some of the larger ones could cause as many deaths as did the attack on the World Trade Center in New York.

But there have to be priorities in our search for national safety. We cannot just spread money evenly around the country like butter on toast, hoping to cover every risk.

Events in London and Madrid have focused attention on how vulnerable our bus, rail, and subway networks have become. While about $15 billion has been spent to increase the safety of airplanes and airports, a mere $250 million of federal funds has been spent on mass transit in the last three years.

But Homeland Security Secretary Michael Chertoff wasn't wrong when he said that an airplane in terrorist hands could kill 3,000 people while a subway bomb ''may kill 30." Nor was he wrong when he said ''a terrorist attack on the two-lane bridge down the street from my house is bad but has a relatively low consequence compared to an attack on the Golden Gate Bridge."

With the fourth anniversary of 9/11 coming up at summer's end, it is well past the time to take stock and stop thrashing about when it comes to homeland security. As William Millar, president of the American Public Transportation Association, recently said, it is simply impossible to protect every piece of a national transportation network upon which 32 million people depend daily.

The focus has to be on preventing catastrophic, society-destabilizing, skyline-altering disaster such as could be rendered by chemical, biological, or, God forbid, nuclear attack. I am not saying do nothing about guarding against bombs on the subway, but -- and this is a hard thing to say -- we are going to have to live with a certain level of conventional explosions such as hit the London underground. The London police are well aware that the events of July 7 were pretty low on the terrorist Richter scale.

We are going to have to do more to protect this nation's ports, through which millions of containers pour without benefit of sufficient inspection. And ''port of entry" doesn't just mean a seaport. It can mean the final destination in which the container is opened, which could as easily be Denver as Philadelphia.

We are going to have to reconsider the entire color-coded approach to security. Without any specific threat, we cannot be going up and down the color spectrum every time there is an attack somewhere in the world. Why wouldn't a copycat attack on Boston's mass transport system just as likely come after the code had retreated to yellow?

We have to rationalize risk as an insurance company does. Just as it costs more to insure your car in New York City than in the country, so should Homeland Security spend its money guarding against big risks in target-rich places, not waste its resources on surveillance cameras in the tiny ferry ports of rural Maine.

H.D.S. Greenway's column appears regularly in the Globe.