I have not had time to read recent papers by Paul Krugman and Robert Lawrence, but I won’t be surprised if this bottom line from the Economist is right:

Given the lack of fine-grained statistics, none of these studies settles the debate. It is possible that globalisation is becoming a bigger cause of American wage inequality. But contrary to the tone of the political debate, and the thrust of Mr Krugman’s commentary, the evidence is inconclusive. “How can we quantify the actual effect of rising trade on wages?” Mr Krugman asked at the end of his paper. “The answer, given the current state of the data, is that we can’t.”