The essential factor of military success is speed, that is taking advantage of others' unpreparedness or lack of foresight, their failure to catch up, going by routes they do not expect, attacking where they are not on guard. This you cannot accomplish with hesitation.
Teller contended, not implausibly, that hydrogen bombs keep the peace, or at least prevent thermonuclear war, because the consequences of warfare between nuclear powers are now too dangerous. We haven't had a nuclear war yet, have we? But all such arguments assume that the nuclear-armed nations are and always will be, without exception, rational actors, and that bouts of anger and revenge and madness will never overtake their leaders (or military and secret police officers in charge of nuclear weapons). In the century of Hitler and Stalin, this seems ingenuous.
In Iraq and Syria, American leadership - including our military power - is stopping ISIL's advance, instead of getting dragged into another ground war in the Middle East, we are leading a broad coalition, including Arab nations, to degrade and ultimately destroy this terrorist group.
I think in many ways, the Spanish Civil War was the first battle of World War II. After all, where else in the world at this point did you have Americans in uniform who were being bombed by Nazi planes four years before the U.S. entered World War II? Hitler and Mussolini jumped in on the side of Francisco Franco and his Spanish nationalists, sent them vast amounts of military aid, airplanes, tanks - and Mussolini sent 80,000 ground troops as well - because they wanted a sympathetic ally in power. So I think it really was the opening act of World War II.
I would say that I have been consistent in my broad view of how American power should be deployed, and the view that we underestimate our power when we restrict it to just our military power. We shortchange our influence and our ability to shape events when that's the only tool we think we have in the toolbox.
Tonight, we gather to affirm the greatness of our nation - not because of the height of our skyscrapers, or the power of our military, or the size of our economy. Our pride is based on a very simple premise, summed up in a declaration made over two hundred years ago.