I find the thrust of this paper by Hiau Looi Kee, Marcelo Olarreaga & Peri Silva entirely unsurprising, but it’s worth passing along nonetheless:

This paper addresses two main questions: Can lobbying by Latin America’s exporters in the US explain the observed pattern of tariff preferences? And if yes, what is the return on $1 dollar of lobbying in the United States by Latin American exporters?

Results suggests (sic) that lobbying by Latin American exporters to the US government can indeed help explain the variation in tariff preferences across products and countries. Moreover, the returns to foreign lobbying seem to be relatively high, around 50 percent. Finally, contrary to the empirical literature for the United States described above we found very low values for the estimates of the weight granted to social welfare in the government’s objective function (around two times the weight granted to foreign lobbying contributions), which underscores the importance of foreign (and domestic) lobbying in determining US trade policies.