I don’t understand what happened yesterday. The pundits called it an act of war. My grandmother likened the attack to Pearl Harbor. A classmate of mine attributed Tuesday’s events to evil incarnate.

Yet no comparison seems right to me. Yesterday’s cruel hijackings and attacks on the World Trade Center in New York and the Pentagon in Washington are incomprehensible—for their infamy and not for some abstract sense of evil, but because I have a friend who worked in the financial district of New York, and I don’t know if he is alive. Residents in my house made frantic telephone calls to check on the health of parents who were visiting the Pentagon. Yesterday is simply incomprehensible because, for the first time, I felt an irrational fear each time an F-16 fighter plane passed over Cambridge and wondered if, this time, the terror would come to me.

And so, today, I understand that we have crossed a threshold to a new era of warfare. Though we have been attacked, this is not a conventional war. We have no identifiable enemy. There is no army at which to strike back. There has been no battle.

Instead, there were anonymous attacks on American civilians in New York and public servants in Washington, D.C. For sure, an organized war would be far more satisfying than our present situation.

In comparing yesterday’s events to the attack on Pearl Harbor in 1941, we can remember a time that we fear, but when we also had a strange sense of pride as well. After sustaining enormous damage in Pearl Harbor, America mobilized, entered World War II and molded itself into the international protector of democracy and freedom.

Yesterday’s events share the same sense of violation that Pearl Harbor caused: the frustration when distinctly American places are damaged.

The consequences of yesterday’s attacks will not be like those from Pearl Harbor. For after Pearl Harbor, America entered a war and fought to defend the values that we still respect today. Tuesday’s terrorist attack gives us no opportunity to struggle for that in which we believe.

If I were 21 in 1941, I could have enlisted in the armed services and joined the United Service Organizations. I could have taken a stand for my nation. Today as a young adult, I can donate blood in the hopes of saving victims, but I cannot strike directly at the cause of Tuesday’s horror. I can’t stop the murderers.