The United States basks in the strength of their defense force and this area is one that wouldn't be weakened even with all this economic crisis and unemployment going on. The United States is under the constant watch of alot of foes, so no matter the cost they cannot let their guard down in military strength/power.
So they are forced to print.
To save from depth deflation
To remain current military strength
To face 30% unemployment.
This is indeed a "doom loop" and it won't last long till huge global monetary crash (maybe not 2 years, but i doubt that nothing will change in 10 years time frame).