If President Obama's latest budget proposal is followed, the national debt would grow to represent 90 percent of the total U.S. economy by 2020, according to a Congressional Budget Office (CBO) analysis.
The CBO projects that under President Obama's proposed budget, the U.S. publicly held debt would grow from $7.5 trillion - or 53 percent of the nation's Gross Domestic Product (GDP) - at the end of 2009 to $20.3 trillion - or 90 percent of the GDP -- by the end of 2020. The interest on the debt alone, says CBO, would more than quadruple, reaching $900 billion annually by 2020.
The publicly held debt, also called the "national debt" includes all monies owed by the United States government to persons and institutions outside the government. For instance, at the end of 2009, the United States owed China $895 billion and Japan $766 billion. U.S. Debt to foreign nations totaled about $3.7 trillion at the end of 2009, according to the Treasury Department.
Also See:
About the President's Annual Budget Proposal
Congress Increases US Debt Limit Again
The "Debt" and the "Deficit" (US Economy)

Comments
Great article, Robert.
The CBO doesn’t count the debt the government owes itself – which is essentially Social Security. The money taxpayers have paid into Social Security is lent by the U.S. Treasury to other government departments. This debt does count, because Social Security must be paid for.
The real debt is not $7.5 trillion, but over $12 trillion. The U.S. is already at 80% of GDP.
Want to know what happens to great economies that stagger under so much debt? Look towards the east – Japan’s economy has been sluggish for decades.
Kimberly
This scenario will only happen if the BUSH tax cuts for the wealthy are extended. It is the alternate scenario. The baseline scenario (if the tax cuts lapse as they should) is stable and more realistic. http://en.wikipedia.org/wiki/File:CBO_-_Public_Debt_Scenarios_-_June_2011.png
Want to fix the underlying problem? Quit electing Republicans that want to give unnecessary tax breaks to corporations and the wealthy.