If you are an individual, using your home multiple times as loan collateral can get you in trouble.
However, it now appears he used the same collateral--a motley collection of small rental town houses and his own residence--over and over. Vaughan's $3.25 million home, for example, now has $79 million in mortgages against it. [source]However, if you are the U.S. Federal government, you can do this without raising an eyebrow.
The U.S. ran a record $1.42 trillion deficit in fiscal 2009. Fiscal years begin Oct. 1. [source]