With no package, a trigger mechanism will cut $1.2 trillion from spending, half from the military. Defense Secretary Leon Panetta has warned that the new cuts, on top of $350 billion in previous cuts, will "totally hollow out the force."
Congress might find a way to undermine the trigger cuts, but that simply would put off the inevitable reform of Medicare, Medicaid and Social Security.
It's like continuing to charge things on your credit card when you barely can meet the minimum payments. The later the fix the deeper the bite.