The odd part about SS spending is it's vary low friction Income redistribution so it has little impact on the economy where Defense spending has a such a huge negative impact. However, such a large portion is put into the general fund the SS savings is basically just income tax.

http://carriedaway.blogs.com/carried_away/2005/04/us_governm...

PS: US GDP growth is slower than the rest of the world so it's hard to think why people think we are such a great example of growth..