On Dec. 7, 1941 — 65 years ago — pilots from a Japanese carrier force bombed Pearl Harbor. They killed 2,403 Americans while destroying much of the American fleet and air forces stationed in Hawai'i.

The next morning, an outraged United States declared war, which ended less than four years later with the destruction of most of the Japanese empire.

Sixty years after Pearl Harbor came another surprise attack on U.S. soil. It was, in some ways, worse than the "Day of Infamy."

Nearly 3,000 people died in the Sept. 11 attacks — the vast majority of them civilians. Al-Qaida's target was not an American military base far distant from the Mainland. Rather, they suicide-bombed the United States' financial and military centers.

It's been five years since Sept. 11. After such a terrible provocation, why can't we bring the "global war on terror" to a close?

Is our generation less competent? Not really. The United States routed the Taliban from Afghanistan by early December 2001. America's first clear-cut victory against the Japanese, at Midway, came six months after Pearl Harbor.

Do we lack the unity of the past? Perhaps. But we should remember that after Pearl Harbor a national furor immediately arose over the intelligence failure that had allowed an enormous Japanese fleet to approach the Hawaiian Islands undetected. Are we in over our heads fighting in both Afghanistan and Iraq?

Hardly. Within days after Pearl Harbor, the U.S. found itself in a three-front war against Germany, Italy and Japan — an Axis that had won a series of recent battles against the British, Chinese and Russians.

But there are significant differences between the "global war on terror" and World War II that do explain why victory is taking so much longer this time.

The most obvious is that, against Japan and Germany, we faced easily identifiable nation states with conventional militaries. Today's terrorists blend in with civilians, and it's hard to tie them to their patron governments or enablers in Iran, Saudi Arabia, Syria and Pakistan, who all deny culpability. We also tread carefully in an age of ubiquitous frightening weapons, when any war at any time might without warning bring in a nuclear, non-democratic belligerent.

The limitations on our war-making are just as often self-imposed. Yes, we defeated the Axis powers in less than four years, but it was at a ghastly cost. To defeat both Japan and Germany, we averaged over 8,000 Americans lost every month of the war — compared to around 50 per month since Sept. 11.

The United States has encouraged its citizens to shop rather than sacrifice. The subtext is that we can defeat the terrorists and their autocratic sponsors with just a fraction of our available manpower — ensuring no real disruption in our lifestyles. That certainly wasn't the case with the Depression-era generation who fought World War II.

And in those days, peace and reconstruction followed rather than preceded victory. In tough-minded fashion, we offered ample aid to, and imposed democracy on, war-torn nations only after the enemy was utterly defeated and humiliated. Today, to avoid such carnage, we try to help and reform countries before our enemies have been vanquished — putting the cart of aid before the horse of victory.

Our efforts today are further complicated by conflicting Internet fatwas, terrorist militias and shifting tribal alliances; we are not always sure who the enemy cadre really is — or will be.

So paradoxes follow:

A stronger, more affluent United States believes it can use less of its power against the terrorists than a much poorer America did against the formidable Japanese and Germans.

World War II, which saw more than 400,000 Americans killed, was not nearly as controversial as a war that has so far taken less than one-hundredth of that terrible toll.

And after Pearl Harbor, Americans believed they had no margin of error in a war for survival. Today, we are apparently convinced that we can lose ground and still not lose either the war or our civilization.

Of course, by 1945, Americans no longer feared another Pearl Harbor. Yet, we, are still not sure we won't see another Sept. 11.

Victor Davis Hanson is a classicist and historian at the Hoover Institution at Stanford University. Reach him at author@victorhanson.com.