Since we are doing it with borrowed money I would suggest that in the absence of the war that we do not find something else to spend it on, we just don't spend it.
That being said I would like to point out that sometimes not fighting a war is more expensive than fighting one. Resistance to terrorist or tyrants is not economical in the long run.

Liberals are like a "Slinky". Totally useless, but somehow ya can't help but smile when you see one tumble down a flight of stairs!