The big news of the day is that the Chinese authorities have allowed the renminbi to depreciate by 2%. This has triggered the normal sensationalist warnings about an upcoming "currency war".
I must say I find these warnings to be rather uneducated about monetary theory and about monetary history. Hence, normally it is said that devaluations have the purpose of improving "competitiveness" and that such policy is an act of beggar-thy-neighbor and that this kind of policy caused a protectionist spiral during the Great Depression.
However, this is not in fact correct. First of all if a country needs to ease monetary policy to stabilise nominal spending then it follows logically that the currency of the country will have to depreciate. That, however, need not be the purpose, but rather a side-effect of monetary easing. Rather it is normally so that if we look at historical examples of large devaluations - for example the US in 1933 or Argentina in 2001-2 then the primary effect of the monetary easing is a sharp recovery in domestic demand, which actually tends to benefit exports from neighboring countries rather than hurt them.
Furthermore, during the 1930s it was not the countries which gave up the gold standard and devalued, which introduced protectionist measures. Rather it was the countries which refused to give up the gold standard, which instead increased tariffs and other protectionist measures.
Furthermore, we are in a situation of still relatively meager global growth and deflationary tendencies around the world and in such a world monetary easing should be welcomed rather than criticized as it will help spur global growth.
Finally it is somewhat paradoxical that anybody would criticize a 2% devaluation, while not at the same time demand that commodity exporters like Russia, Brazil and Norway - which have seen currencies weaken substantially recently - should do something to prop up their currencies. Obviously these countries should not be criticized for allowing their currencies to weaken in response to a negative shock to the economy, but neither should China. China's devaluation is not a hostile act - it is an attempt to stabilize Chinese aggregate demand and as such the policy should be welcomed.
Give up the fine-tuning and let the renminbi float
That being said I also think that China's devaluation is rather foolish - simply because I want more and not less. In my view the right policy would be for China to swiftly move towards a free floating renminbi and a total liberalization of capital and currency flows and to introduce a policy to stabilize nominal demand (NGDP) growth in the Chinese economy.
Hence, every other large economy in the world - with the exception of those trapped in the euro - have floating exchange rates and in general the purpose of monetary policy in these countries is to provide nominal stability in some form. China should of course do the same thing. That would be to the great benefit of China and would once and for all stop the silly discussion about "competitive devaluations".