If I'm right and there will be another two years of cheap money then some of those costs will become more evident - even if Mr Greenspan does get his name on a building after all.. There is the damage to household savings.And then there are questions about the dollar. The US has got away with only modest weakening of the dollar because Japan and China have been prepared to finance the US current account deficit by buying dollar securities. At some stage they will have to pare back their purchases, maybe soon.So cheap money is a policy where in the US case at least the benefits are obvious and immediate and the costs less obvious and longer term. There is the way it has forced cash into unwise investments in the search for yield.

There is the extent to which it has worsened the current account. There are hot-spots where prices have been almost as frothy as in the hot-spots in the UK. There is the concern, noted above, that the US has been able to hold down inflation by a surge in imports of cheap goods and that surge is unsustainable.There are several questions about the other distortions of cheap money. You should not blame the Fed for the rise in the price of oil, the markets' current concern, but you can blame it for home-generated inflation in the US That seems now to be becoming more evident You can blame it for inflated property prices.

But I do think when the economic history books are written they will focus as much on the failure to tighten policy in 1999 as on the use of very low interest rates to pull the country through the 2001 recession.But it is not too early to be asking some questions about the costs of cheap money - actually free money, since the US has negative real interest rates - and whether these costs will become more evident in the next couple of years.There are several questions about inflation. He could, if he wanted to, presumably run right through his new four-year term. Indeed, too-cheap money in 1999 helped underwrite a surge in US retail sales (bottom right-hand graph).It is far too early to be judging Mr Greenspan's term of office and not just because he has at least another two more years in post. But if you look at that graph, you can see the main deterioration started in 1998, under the Clinton administration and just at the time when arguably the Fed should have started tightening policy if it was to prick the share-market bubble early. Fiscal policy has played a part in boosting demand, particularly since the present administration's tax cuts.