Deficits and Debt

As the government contemplates pushing the budget deficit for 2009 to nearly a trillion dollars, the question of who will or even who can buy that debt is being asked in an article by The Economist.
Government bonds are well known for their value as stable investments, even if not known for being otherwise large-returning investments. But as more governments run deficits and are financing it with debt, will there be a glut, driving returns even lower?
The model they point to is japan, where for nearly 20 years investors have taken government debt despite it returning an even lower amount than US debt is presently. But this option is unlikely as the primary market for this was not foreign investors.
The US, it looks right now, may not have to be too concerned. With the entire world facing challenges, the American dollar has actually risen against major currencies, while previously strong currencies such as the pound, have lost value. But there may still be a need for domestic purchasing of government bonds, a more realistic event if central banks continue to lower rates and make government bonds more attractive investments comparatively.
The real issue they see, is in economic recovery, which will likely come well before any return to balanced budgets, meaning that then government debt will be competing against more competitive investments, making running deficits at that point more expensive.