Counterparty of last resort?

``The Fed can deny all it wants that it is considering purchasing mortgage-backed securities. That is the economic effect of this arrangement. The Fed is buying up mortgage-backed securities and other unspecified assets at "the value of the portfolio as marked to market by Bear Stearns on March 14, 2008."... We've had central banks touted as lenders of last resort, market-makers of last resort, and fools of last resort. We'd better think very carefully before letting the Fed become a derivatives counterparty of last resort.''