The domestic arms race

Last April, Vin Suprynowicz of the Last Vegas Review Journal authored a piece called "This Time The Arms Race is Domestic.". In it, Suprynowicz said, in part:

One thing should be obvious, however. In little more than a decade since the Sept. 11, 2001, attack on the World Trade Center, the federal government has created a vast new domestic police force, massively armed and busily working to get us accustomed to what looks more and more like an army of domestic occupation. 

And because American civilians are simultaneously gunning up in unprecedented numbers, in part out of concern that the gun grabbers' agenda may be back on the front burner in any Obama second term, could this be considered an arms race?

How many billions of dollars have been been spent on arms and ammo by both the U.S. Department of Homeland Security and by private U.S. citizens since that was written?