Today CBO released the Long-Term Budget Outlook. Under current law, the federal budget is on an unsustainable path—meaning that federal debt will continue to grow much faster than the economy over the long run. Although great uncertainty surrounds long-term fiscal projections, rising costs for health care and the aging of the U.S. population will cause federal spending to increase rapidly under any plausible scenario. Unless tax revenues increase just as rapidly, the rise in spending will produce growing budget deficits and accumulating debt. Large budget deficits would reduce national saving, leading to more borrowing from abroad and less domestic investment, which in turn would depress income growth in the United States.
Keeping deficits and debt from reaching levels that could cause substantial harm to the economy would require increasing revenues significantly as a percentage of gross domestic product (GDP), decreasing projected spending sharply, or some combination of the two. Making such changes sooner rather than later would lessen the risks that current fiscal policy poses to the economy. Although the policy choices that will be necessary are difficult, CBO’s long-term budget projections make clear that doing nothing is not an option: Legislation must ultimately be adopted that raises revenue or reduces spending or both. Moreover, delaying action simply exacerbates the challenge, as is discussed in the report.
I ran some of the current numbers from the CBO's historical data series. Here are the relevant charts (click for a larger image):
