Chart about half way down the page shows how much we spent on WW2. We have, and can, spend as much as half our GDP on Defense if needed. Feelings are not facts. People around here got to stop this bad habit of stating their emotion based opinions as statements of fact.
http://eh.net/encyclopedia/article/tassava.WWII
Yes in a national emergency, the entire country can do incredible things and sacrifice much. They also had to ration just about everything during WW2 right down to silk and panty hose and buy war bonds every year. We could spend half of our GDP on defense if we got into WW3 with Russia, but we certainly couldn't do it year in and year out. Not even close. To suggest that we could spend $5 trillion a year on defense without tripling taxes and ruining the economy and destroying this country is ludicrous.