As Congress debates the establishment of the Department of Homeland Security, members will probably recall the trademark growl of that late, great 20th century philosopher, James Durante:

"Ev-ree-buddy wants ta get into duh act."

A whole generation of Americans grew up being told by Smokey the Bear that "only you" can prevent forest fires. Post Sept. 11, various pundits and elected officials tell you that "you" – with Homeland Security as your agent – can prevent most, if not all, acts of terrorism.

Well, Smokey didn't actually say that all forest fires could be prevented. They can't. For example, no one can prevent lightning from starting a forest fire. About the best anyone can do is to keep a forest fire – once started – from burning out of control. Frequently, the U.S. Forest Service can't even do that. We very nearly lost Los Alamos National Lab a few years ago to a fire intentionally started by the U.S. Forest Service.

So don't expect the Department of Homeland Security – no matter how organized and staffed – to prevent all acts of terrorism. Nor even to prevent all horrific acts of terrorism. About the best we can hope for is that Congress will dedicate our available resources to preventing those horrific acts that are preventable.

What's the most horrific act of terror you can think of? How about terrorists somehow acquiring a nuke or the makings of one, smuggling it into the country and nuking you in your jammies? Well, as it happens, that's a horrific act that can be prevented.

But not by Homeland Security.

Acquisition of a nuke or the makings thereof by terrorists can be prevented. But at the source, not here in the homeland. For example, terrorists will need hundreds of pounds of highly enriched uranium to make their own nukes. There are less than a dozen sources of HEU in the world. Presidents Bush and Putin have recently announced that they – in cooperation with the International Atomic Energy Agency – will prevent terrorists from acquiring any of that HEU.

Of course, preventing terrorists from smuggling a nuke – once obtained – into our country would be a job for Homeland Security. But it would be a very expensive mission-impossible.

So, conceding failure at the borders, Homeland Security may seek to train and equip hundreds of thousands of policemen, firemen, doctors, paramedics and nurses to respond to a terrorist use of a nuke. That would be a waste of precious resources, especially if we are able to prevent terrorists – as we most likely will – from acquiring nukes.

Yet, if you are not vigilant, Congress will give in to those hundreds of thousands of constituents who want to "get into the act." Billions will be spent, trying to prevent things that can't be prevented, or don't need to be. Consequently, Congress won't be able to fully fund programs that actually can prevent horrific acts of terror.

What's next on your list – after being nuked in your jammies – of preventable horrors? Well, how about this? In December 1988, terrorists detonated a pound of plastic explosive, hidden in a portable radio in "checked" luggage, over Scotland, causing Pan-Am Flight 103 to break-up in mid-air.

Since then, checked luggage has been "spot checked," sometimes by dogs specially trained to sniff out explosives. Congress has now required that, by year's end, all checked baggage at all U.S. airports is to be screened by explosive detection systems. These systems – long under development – are allegedly capable of scanning at least 600 bags per hour and making go/no-go decisions as they glide by on a conveyor belt.

There are two basic EDS types, 1) computed tomography and 2) explosive trace detection machines. A CT machine is much akin to a medical CAT-Scan device. An ETD machine is somewhat akin to your state's exhaust emissions tester. Try to imagine either one performing 600 scans an hour.

These fast hi-tech machines are equipped with artificial intelligence packages to decide what all the data their sensors are taking means. Automated data evaluation and decision making is critically important, since these machines will be operated by brethren of those mental giants who now scan your carry-on luggage – sometimes with their x-ray machine unplugged.

Soon Homeland Security will have thousands of these EDS machines at airports around the country. Can they be trusted to make the right decisions? Can they find all the plastic explosives terrorists may secrete in checked luggage?

Maybe we ought to keep a few of the trained dogs around, just in case.