The QE ad nauseum is pumping billions of worthless currency into the economy. This will inevitably produce inflation. The Fed can only keep interest rates artificially low for a limited time, and when the fertilizer hits the ventilator, those rates will, to borrow a phrase, necessarily skyrocket. How high it will go is anybody's guess, but if we hit 15% which we saw in the Carter years and don't borrow another dime, debt service will hit 2.14 trillion, which is very close to total tax revenues. Once the debt service exceeds tax revenues, the economy will collapse, making what we saw in 08 look like an elementary school picnic.