Okay, that might be a bit of an overstatement, but there is no way to turn the United States into a terrorist proof zone.
Don Larson linked to a Reuters story about proposals to protect nuclear power plants from possible aerial assaults.
The problem is that the number of ways to inflict mass murder is so large that you can never plug all the holes in the dike.
Here’s a little recipe to kill a few thousand people. Find a pharmaceutical manufacturing facility nearby. Figure out where they store their chemicals and find a way to blow up that plant. Results — probably tens of thousands of deaths (think Bhopal, India).
For example, Pharmacia has a couple of plants here in Kalamazoo. One of the important chemicals used in pharmaceutical production are cyanide and related compounds. If a terrorist could successfully blow up the storage facility where those compounds are kept, they would probably kill tens of thousands of people in just the first couple hours.
(The amusingly macabre thing about this particular area is that we might not need terrorists to cause this disaster. In the sort of decision that only Americans would make, the city decided to place its airport right next to the pharmaceutical plant, meaning several dozen planes fly over the plant either taking off or coming in for a landing. There have been a handful of crashes near the facility, and it’s only a matter of time until a commuter plane accident wipes out everybody in lower Michigan and upper Indiana).
And if we sat down and thought about it, I’m sure we could think of dozens of ways to kill thousands of people. There’s just no way to childproof the world.