I think Krugman was trying to make the case for why many smart people don&#x27;t seem to understand how the theory of Comparative (as opposed to absolute) Advantage works.<p>I don&#x27; think he was arguing that that theory is the be all and end all of trade policy. The theory is a abstract model of the world - it is a useful guide like all abstract models but does not capture the world in all its complexity.<p>Both theoretically and practically, over the last 30 years, there is increasing evidence that Free Trade effects - like everything -  depends on context and policies.<p>Krugman himself writes alot about this on his blog. Can&#x27;t search for everything right now - but here is an example from a few weeks ago:<p><a href="http:&#x2F;&#x2F;krugman.blogs.nytimes.com&#x2F;2016&#x2F;04&#x2F;20&#x2F;101-boosterism&#x2F;" rel="nofollow">http:&#x2F;&#x2F;krugman.blogs.nytimes.com&#x2F;2016&#x2F;04&#x2F;20&#x2F;101-boosterism&#x2F;</a><p>He has also been consistently lukewarm on the TPP trade deal exactly because of these issues:<p><a href="http:&#x2F;&#x2F;krugman.blogs.nytimes.com&#x2F;2015&#x2F;04&#x2F;26&#x2F;this-is-not-a-trade-agreement" rel="nofollow">http:&#x2F;&#x2F;krugman.blogs.nytimes.com&#x2F;2015&#x2F;04&#x2F;26&#x2F;this-is-not-a-tr...</a><p><i>&quot;One thing that should be totally obvious, however, is that it’s off-point and insulting to offer an off-the-shelf lecture on how trade is good because of comparative advantage, and protectionists are dumb.&quot;</i>