Unless the government was to engage in 'deficit spending' -- e.g. spending money it doesn't have by seeking loans from foreign countries.

Oh course, that would never happen. :)

Our deficit is significant but our 13.84 Trillion GDP means deficit spending of 1/2 Trillion a year is less than 5%. His graph placed taxes around 12% of GDP which is just so far from the truth that it's almost meaningless.