Former Federal Reserve chairman Alan Greenspan has declared that he is not "overly concerned" by the recent decline in the dollar.Speaking to Bloomberg, the economist indicated that the biggest danger facing the US as it enters recovery is that its national debt will become unserviceable.He said faith in the country's ability to repay its debts has acted as a "cushion" that allowed the dollar to remain such an important currency globally.However, Mr Greenspan added: "There is no question that the cushion is going down."Looking forward to a strategy that will help to restore faith in the US economic and financial system, the former Fed chairman suggested that banks and investment houses deemed too big to fail should be broken up to prevent the kind of shockwaves created by the collapse of Lehman Brothers in September 2008.Despite a modest moderation in net long positions on the dollar, Daily FX has concluded that there is little opportunity for a recovery in the greenback in the short-term, with losses against the likes of the yen and euro expected to continue.