You seem to imagine that there is one simple thing called "the economy," that revives by any monetary injection whatsoever. But that "economy" is at best a gross abstraction, compounded of millions of individual personal acts of production and consumption and at worst it is nothing but a fiction

The state of "the economy" is appropriately judged, not by gross indicators, but by the ability of ordinary human beings to improve their lives and communities by their labor: if goods and services become harder to obtain, the corresponding rise in prices may leave the gross indicators unaffected -- but surely the person who now works twice as long to buy the same meat and potatoes notices the difference

The country can invest in war or infrastructure or in other ways: the dividends will be quite different. An investment in infrastructure produces a lasting convenience; an investment in war produces blast trash, filled coffins, and a generous supply of mentally or physically wounded veterans. Simple logic should convince you that a war economy necessarily produces scarcities and price rises. Long-term medical services must (of course) be supplied to the casualties, and this increases the general cost of health care. National Guardsmen in the war theatre could have been otherwise employed, as survivors of Katrina in New Orleans will no doubt long remember

The Iraq war actually helped the economy? I would laugh but can't because I want to cry too badly: the war helped a few war profiteers, like Halliburton (who promptly packed up and left the country); it screwed the rest of us, at the gas pump and in a thousand other ways