We were attacked, the first attack on US soil by a foreign country since the War of 1812. The attack did indeed wake a "sleeping giant" (although whether or not Yamamoto ever made the apocryphal statement forever attributed to him is a matter of some debate), thrusting the nascent power of the United States into the Second World War on the side of the Allied powers. It was not the evils of Nazi Germany that brought us into the war but the brazen attack on Pearl Harbor.
Today is, has been, and may very well continue to be Pearl Harbor Remembrance Day, a day set aside to remember the events of December 7th, 1941, a day that has lived in infamy ever since. 71 years - nearly an entire lifetime - have passed since that attack, and the world has changed dramatically in those years. Eleven years ago saw another massive attack on America, with a radically different response. Rather than the overwhelming and crushing response of the 1940s, the 2000s saw a more surgical, precise response that very specifically targeted leadership of the groups responsible for the attack.
Granted, the two attacks are quite different - Pearl Harbor was a coordinated effort from an enemy nation, the very epitome of an act of war. Our sovereign ground was attacked by their war machine - very little shades of grey there. The September 11th attacks saw our own technology and rules used against is - with little more than sharp knives, some flight training, and a grim resolve, Islamic terrorists killed thousands of Americans inside the continent. It's natural that the responses differ - in 1941 the enemy was crystal-clear; some sixty years later, nowhere near so much so.
There are rumors that the US knew of an impending attack on a US installation in the weeks and months prior to the Pearl Harbor attack. Warnings three months prior hinted at an impending assault, but were discarded as unreliable based on an obviously faulty assessment of Japan's naval capabilities. The more conspiracy minded offer many reasons why the attack was "allowed" to proceed: drawing an isolationist United States into the war being the most prominent (and likely, if it were true that the attack was "allowed" to happen).
There's a line in the Batman "The Dark Knight Returns" where Commission Gordon explains Pearl Harbor to the incoming commissioner. He explains how the reaction to the attack - fear, then anger, then resolve - allowed the military might of the United States to go to war in Europe to stop the Axis forces. The horror of Pearl Harbor was needed to rouse the United States to action to stop a much larger horror. Gordon explains that even if the attack had been "allowed" to happen, that the events were simply too big to judge; that the good of stopping the Nazis more than offset rumors of ignoring the attack.
Seventy one years ago today, we were attacked. Take a moment to remember the soldiers, sailors, and airmen that lost their lives in the attack. Pray that we never again see an attack of that magnitude on our soil - but prepare as though we will. Our enemies may not gather under a single flag or alliance, but they are indeed real, prepared, and ready to kill us in large numbers should we ignore them as we did the Japanese some three and a half score prior.
That is all.