If I have good reason to expect you to hit me, I will hit you first or run away and hide.
A country like the US can't hide and can't run away. Our borders are open and our country is free. That makes us vulnerable, but vulnerable is better than what the Soviet Union imposed on eastern Europe.
Correction. Germany declared war on the US BEFORE the US declared war on Germany. A pre-emptive strike is what the Japs did to us. They did it because they understood war was inevitable and figured their only chance of success was to deliver a crippling blow right off. Just for the record we considered their Pearl Harbor strike a very low down, dastardly, treacherous act. Our current policy is not pre-emption though, it is more properly called pre-ventative. If we had spotted the Japanese fleet off the Hawaiian coast and hit it before they hit us that is pre-emptively striking a blow before a sure and immanent blow is received. The policy Bush outlined is that we will strike anyone we consider to have the potential to be a threat. Big, big difference.
cordially,