As we observe the eighth anniversary of al-Qaida's attack on our nation, I propose that we imagine ourselves under attack, albeit a more insidious, less spectacular one.

No, I'm not trying to spread unhappiness. I am instead hoping we can use the memory of that tragic day to improve our lives and those of our children.

The date of Sept. 11, 2001, is seared into my memory. When I first saw a plane fly into a building, I thought it must have been an errant commuter-plane accident.

As we all now know, it was not a commuter plane but a commercial jetliner. Not an accident, but a coordinated attack by terrorists determined to die for their beliefs. Young terrorist men, 19 of them, died that day. They took the lives of almost 3,000 Americans and the naivete of a generation of others.

Six weeks before the tragic day, I gave birth to my second child. My nights were sleepless after the attack, from rocking him to sleep in the early hours, and from newfound anxiety. Listening to the military aircraft fly over our home in Atlanta -- a few miles from Dobbins Air Reserve Base -- I worried about his safety and the world in which he would grow up.

"We have come together with a unity of purpose because our nation demands it," The 9/11 Commission Report said. It continued, "The nation was unprepared."

No one is ever prepared for tragedy.

"The most important failure was one of imagination," noted the report. "We do not believe leaders understood the gravity of the threat."

"Imagination," according to Albert Einstein, "is more important than knowledge."

Imagine our enemies infiltrating our internal structures and causing our nation's health, economic and educational systems to deteriorate. Even if they haven't, what if we responded as if they had, thereby creating a unity of purpose -- to make America better?

Many of our nation's core areas are indeed under threat. It is up to us to understand the gravity of those threats and to respond.

In the area of health, we must solve our nation's underlying health crisis. In the United States, more than one-third of adults are obese, according to the Centers for Disease Control and Prevention. Obesity creates an enormous burden on personal health (it often leads to other health issues) and on our nation's health. The cost of obesity might be as much as $147 billion per year, according to health economist Eric Finkelstein.