Because of the difference in Discretionary and Mandatory spending. Things like Medicare/Medicaid and Veterans Affairs are Mandatory. Things like the Defense Budget And Infrastructure are Discretionary.  The more Debt Interest, the less Discretionary spending you can do without raising Taxes. Right now, the Interest alone is more than the entire Military Budget and still growing. Soon we will *have* to cut spending and raise taxes just to pay the Interest on what we owe. 'Printing more money' only serves to weaken the Dollar and creates Inflation.