This post is more to provide awareness of good, concise references on the topic than for me to add anything of value to the discussion. Both items are products of the Council on Foreign Relations' 'Renewing America' initiative.
U.S. Deficits and the National Debt is a solid primer on the topic, providing easy-to-read summaries of the major points and links to a host of additional reference material.
What is the Fiscal Cliff? does the same for the holding-our-collective-breath situation due to arrive January 2013. Also know as Taxmegeddon, the 'fiscal cliff' is the umbrella reference for the anticipated (feared) impact of the expiration of some tax relief measures and the implementation of new tax initiatives.
With regard to the CFR/RA 'Fiscal Cliff' item, I'll add only two thoughts: 1) while mentioning the Budget Control Act of 2011 that will impose $55B in spending cuts on the Defense Department for 2013 alone, it doesn't mention the previous spending cuts already levied against DoD to the tune of $48B per year for the next decade also starting this coming year for a combined total of $103B of cuts per year, a reduction of nearly 20% of the base budget; and 2) much of the analysis I've read on the current federal debt ceiling concludes we may hit the new ceiling just prior to the Presidential election this Nov 6 vice early 2013 as many involved in the negotiations last summer had hoped.
This raises the possibility that the White House will have to argue for yet another debt ceiling increase at the worst possible time in a presidential re-election campaign. I wouldn't be surprised to see some artful accounting with the national balance sheet between now and then.