The Credit Strategist's Michael Lewitt has the answer: the Dirty Fed-sponsored TBTF banks.
It should also be noted that the Federal Reserve has accounted for 101 percent of the net Treasury bond issuance during the first four months of 2011 [...]. A new set of buyers willing to be paid virtually nothing for lending to a country that is drowning in debt and debauching its currency will have to be found once the Federal Reserve ends its purchases at the end of June.
Finding such buyers may not be as difficult as some suppose, however. Our friend Christopher Wood, who is always ahead of the curve, notes that the share of US banks’ assets in Treasuries is near historic levels, with only 2.1 percent of U.S. commercial banks’ total financial assets consisting of these confiscatory pieces of paper at the end of 2010.3 This suggests not only that there is scope for the banks to step into the breach and significantly add to their Treasury holdings, but in order for them to do so and earn an adequate spread over their cost of funds, Mr. Bernanke and Co. will wait as long as possible to raise rates so that the massive Ponzi scheme that funds the U.S. government can continue.
That sounds right to me. The Dirty Fed will keep lending to the banks at near zero, allowing the banks to earn free money on the spread buying Treasuries. Of course that means the the TBTF banks are going to get even TBTFer, and it will facilitate Congress' reckless spending, thus delaying -- and worsening -- the eventual day of reckoning.