The heart of the budget blueprint battle that played out last week is over how much ballooning Social Security, Medicare and debt interest costs will crowd out other spending.
That was evident in the competing plans from House Republicans and Senate Democrats, both of which would let Medicare and Social Security grow largely unchecked over the coming decade.
Under the Democrats' budget, those three categories would swell from 9.4% of GDP in 2012 to 11.9% in 2023.
For perspective, that increase is bigger than the 2.2%-of-GDP gap between what Democrats and Republicans want to spend on everything else.
Under the GOP plan, Social Security, Medicare and debt service would rise to a more-modest 11.3% of GDP because interest on the debt wouldn't grow as much.