The Sept. 11 attacks were symbolic in what the terrorists chose to target. When hitting the Pentagon, terrorists caused destruction and loss of life in addition to striking a symbolic blow to the center of America's military.
"It's like saying, ‘You may be a super-power but look what we can do to you,' " Wilhelm said.
"And of course the trade building is symbolic of America's economic might," Wilhelm said.
"There's no doubt about it: We're in a state of war," Wilhelm said.
Often, wars are waged between countries or nation-states, but terrorism makes it more difficult because we don't know who is or how many are attacking us, Wilhelm said.
With so many nations covertly supporting terrorism, "I suspect we're going to be involved in a very long-term involvement with these terrorists," Wilhelm said.
"I think it's naive to think we're going to uproot and eliminate all the terrorist threats to the United States," Wilhelm said.
Right now, it's even unknown how many "sleeper" agents are still in this country. While some were caught in the wake of the attacks, Wilhelm wonders how many more are still out there.
"It's very unsettling and I don't think anyone knows the answer to that," Wilhelm said.
"What that means is the potential for additional attacks is very much a reality. After studying terrorism, especially the potential for it here in the United States, what's frightening is how vulnerable we really are," Wilhelm said.
The biggest fear in Wilhelm's mind is the use of weapons of mass destruction such as chemical and biological agents. Smallpox could be more deadly than nuclear weapons, Wilhelm points out. Because people don't immediately know they're infected, they could easily spread it to others. With the constant movement of people across this country, the disease quickly could spread to far-reaching points from where it was introduced.
"We could have a national epidemic very quickly under those circumstances," Wilhelm said.
Compounding the problem is a lack of vaccine for smallpox and anthrax for the public and, possibly, the military, Wilhelm said.
"It raises the question, since this potential threat has been known for some time, why hasn't the government done something about it?" Wilhelm asked.
"This should be the ultimate wake-up call," Wilhelm said. "Hopefully this is going to change our perspective on things."
One big change Wilhelm would like to see is increased airport security and airplane safety. He cites the protective measures taken by Israel on its planes as a model for this country.
As the situation stands, airlines are responsible for airport security, Wilhelm said. But since airlines are in the profit business, they pay security workers minimum wage and don't provide much training.
"There has to be priority given to protecting human lives," Wilhelm said.
When asked about the history of terrorist attacks on American soil, Wilhelm replied that "up until recently, we've been lucky."
Using Unabomber Ted Kaczynski as an example, Wilhelm said most terrorist acts in this country are committed by crazy individuals or small groups that are neither well-organized nor well-funded.
Unlike the people behind the Sept. 11 attacks, past U.S. terrorists were not taking on the entire country. Timothy McVeigh and his cohorts were aiming at the U.S. government, not the country as a whole, and represented a small group of people who had crossed the line of common sense and rationality, Wilhelm said.
The individuals responsible for these latest terrorist attacks "are extremely well-funded, they're much larger in numbers, and the fact is that they are, I think, the most dedicated fanatics you'll ever meet because they are tying it into their religion," Wilhelm said.
The religious motivation and justification elevate their terrorism to a totally different level, Wilhelm said.
These terrorists hope to destroy what they perceive as enemies of their version of Islam, Wilhelm said. They aim for world conquest and America is the biggest barrier to that, Wilhelm said.