Social Security's disability program is a political quagmire — and a metaphor for why federal spending and budget deficits are so difficult to control. The numbers are too big; the details, too complicated; and the choices, when faced, too wrenching. President Barack Obama's new budget, estimated at $3.5 trillion or more, will raise all these problems. Experience suggests that little will be done to rein in long-term spending and deficits.

Social Security's disability program opens a window on this larger paralysis. Created in 1956, more than two decades after Congress authorized Social Security, the program was initially seen as a natural complement to coverage for retirees. Through sickness or accident, some workers had to retire early. They, too, deserved protection. For many years, the costs were modest. But in recent decades, they have exploded.

Consider. In 2010, Social Security's disability program cost $124 billion plus another $59 billion for Medicare (after two years, disability recipients automatically qualify for Medicare). This exceeded $1,500 for every U.S. household. For the past two decades, disability spending has increased at a 5.6 percent annual rate, compared with 2.2 percent for the rest of Social Security. As a result, disability represents nearly one in five dollars of Social Security spending, up from one in 10 in 1988.