An argument that I think is true—and important—but that I have never been able to get anybody else to pay attention to. Maybe I have just made an algebra mistake, and people are silent because they would feel embarrassed if they pointed that out. But I do not think so:
J. Bradford DeLong (2008): Trade and Distribution: A Multisector Stolper-Samuelson Finger Exercise: One of the basic building blocks of the political economy of international trade is the Stolper-Samuelson result: the shift from no trade to free trade is good for the owners of the abundant factor of production, but bad for the owners of the scarce factor of production. This accounts for why support for free trade tends to be stronger in democratic than in authoritarian regimes. The scarce factor of production tends to be, well, scarce. Hence not many potential voters own a lot of it. Hence the political support for trade protection in any system of government that gives weight to broad, as opposed to strong, preferences will tend to produce trade liberalization.
In the United States, and to some degree in western Europe, things are widely thought to be different—or so the argument goes, The relatively abundant factors of production are things like capital, organization, and technology, which have concentrated ownership. The scarce factor of production is labor. Hence free trade tends to be politically unpopular because it is not in the interest of the majority of potential voters.
This argument of an inconsistency between free trade and the well-being of the majority of potential voters rests substantially on the two-factor example of the Stolper-Samuelson result. It does not fare too well when we generalize to a situation in which there are a number of different factors—even if the ownership of the abundant factors of production is very concentrated indeed....
For λ very close to one, the critical φ* is also close to one. Trade among countries with small differences in relative proportions of the trade-relevant factors of production is good only for households that hold a greater than proportionate share of the initially abundant factor... households for which φ > 1. But as λ moves away from 1 things change. Efficiency and productivity gains grow faster than do the income redistributions from changing factor prices. Even households where the share of ownership of the initially-abundant factor is significantly less than proportionate can benefit. In the limit as N becomes large, the condition on φ for free trade to benefit the household becomes: φ* > ln(λ)/(λ−1)... Read MOAR