Which gets us right back to baling out the creditor banks, except instead of swapping mortgage based securities for t-bills, you've swapped the underlying mortgages, and had to set up a bureaucracy to figure out which mortgages are worthy of being paid off. And probably not solved the liquidity crisis, since some portion of the underlying mortgages are still going to default, unless you go to a plan of paying off any mortgage no matter how irresponsible its origination.