In a number of blog-posts (Paul Krugman's Bicycling Problem, On Bubble Business Bound, The Expectations Fairy) I have examined some of the implications of the theory of secular stagnation. But I haven't up to now argued why I think the hypothesis that Japan and some parts of Europe are suffering from some kind of secular stagnation could well be a valid one.
Strangely, while I would suggest the most obviously affected countries are those mentioned above, most of the debate has centered around the US economy. Since it is not at all clear that the US economy is actually suffering from either a liquidity trap or secular stagnation at this point, this has lead many to question whether the idea might not be ill-founded. The Economist, for example, in a revue article (Fad or Fact) of Teulings and Baldwin's Vox e-book on the topic conclude the concept "remains a baggy one", one which is "arguably too capacious for its own good".