That link has good graphics and explanation. But in the present situation, it may be good to remember the caveat "Past performance is not necessarily indicative of future results". The reason being, the situation is not lack of money as much as lack of trust. Lack of money can be fixed by tweaking FFR, but that won't infuse trust. How are you going to tell all those who lost their pension funds in Europe and Asia that US borrowers really want to pay back their debt? How will you prove to them that a piece of paper stamped AAA by Moody's or S&P has value?
I think the days of splurging on foreign capital are over. We can only lend to each other what we save. And that is not a lot.