Last time I checked, spending is almost $4T/yr, but SS & Medicare account for only $1.6T of it. Military accounts for another $600B. That leaves $1.5T for everything else. Pretty tough to cut half of that.
You forgot Food Stamps and Unemployment ($420 billion) and interest on the debt ($229 billion). You could cut every single penny of non-defense, non-security discretionary spending and you would still be $500 billion short of the $1 trillion in cuts per year you would need to meet the spending reduction goals.
“That leaves $1.5T for everything else. Pretty tough to cut half of that.”
If you eliminated everything not authorized by the constitution it would make a heck of a dent in it.