I suppose I should've put on my economist hat and jumped into this debate about trade. It's going on at tpmcafe and over at Max's place we have some people who weren't invited to the party but who are joining in anyway.
But, just to add my two cents I think it's quite important in understanding this debate to understand that it was news to Kevin Drum the classic trade theory predicts that the opening of an economy to free trade will lead to some factor of production receiving less compensation in absolute terms. It's a testament to how much power the moustache of understanding and other such folks have had on this debate that it's now received wisdom by the lay wonkerati that free trade doesn't have losers. As Josh Bivens points out, we did actually understand this in the early 90s. It's why it was understood (if not necessarily implemented as much as it should have been) that any free trade agreements should be accompanied by, at the very least, some sort of compensation and retraining for those in the losing sectors.
Now we're in this world where people just scream "free trade good!" Well, it isn't good for everyone. There are winners and losers, and all basic trade theory says is that enough extra income is created so that the winners could, in theory, more than compensate the losers for what they lost. But that's "class warfare" and "socialist redistribution" so we don't do that.
It's completely in the self-interest of a nontrivial part of the population to oppose basic free trade legislation. Economists are often loathe to embrace a particular social welfare function, but too many fall prey to embracing GDP as somehow being a metric which is value neutral. In fact all it does is obscure all the things about which we could make a value judgment. A useful measure of something, but certainly not a value-free measure of the nation's economic wellbeing. The income distribution is still there, even if we close our eyes and pretend it isn't.
