Everyone seems to only look at segments of this nation's debt rather than the nation's debt as a whole. The combined debt (government, commercial, and private) is known as "Credit Market Debt" (CMD). Information on this debt can be found in the "Statistical Abstract of the US" at
http://www.census.gov/statab/www/. The tables of interest are located in the banking and income chapters. The latest edition is 2003 covering the 2002 statistics (published in Sep of each year for the previous year).
My interest in CMD came about from a 1990 article in Forbes where the author tried to make an argument that the CMD under Reagan administration was the same as the CMD under Kennedy/Johnson administrations following a tax cut by each. That did not sound correct, so I did some research and found that the author included mortgage debt (government, commercial, and private) in the Kennedy/Johnson years; but, not in the Reagan which skewed things. There was an aside mentioning concern over the mortgage debt; but, was never made a factor in the article.
Some of what I learned from the latest abstract. In 2001, the last year of a Clinton budget, GDP rose 2.62%, GNP rose 2.60%, US Government Debt (USGD) declined 0.15%, and CMD rose 7.48% from the 2000 values. As a result, CMD as a function of GDP rose from 278.37% in 2000 to 291.54% in 2001. In 2002 (the first year of a Bush budget), GDP rose 3.61%, GNP rose 3.29%, USGD rose 7.60%, and CMD rose 7.85% to 303.48% as function of GDP. GNP as function of GDP went from .24% in 2000 to .22% in 2001 to -.09% in 2002 or from a trade surplus to a trade deficit after Bush's budget took effect. The conclusion is that Bush's tax cut from 2001 did not have much of effect in 2002 other than raise the USGD and increase the trade deficit. It also should be noted that during the Clinton years of USGD decline (-1.39% in 1998, -1.89% in 1999, -8.04% in 2000), GNP significantly rose (5.75% in 1998, 5.61% in 1999, and 5.93% in 2000). Buying down debt would appear a better solution than a tax cut to stimulate the economy because the government infuses money into the private sector without entering into competition with the private sector to borrow money.