The Philippines used to be an American colony. Its main exports to the mainland–which were not subject to tariffs because, well, the Philippine islands weren’t a different country–were sugar and copra. Sugar (from sugarcane) was cheaper and of higher quality than domestically-produced sugar, which comes primarily from sugar beets. Copra is refined into coconut oil, which competed with other vegetable oils, animal oils and fats, and fish oils. In the 1930s, this especially meant cottonseed oil, which was turned into soaps. It also meant butter, because of recent innovations that meant that coconut oil could be partially hydrogenated and turned into margarine.

Does the desire for protection from tariff-free sugar and copra imports explain the decision to grant the Philippines independence? The point is this: get the Philippines outside of our borders, and we can impose tariffs. Let’s look at cotton, sugar beet, and milk production across the states. Let’s also throw in sugar cane and the percentage of a state’s population that is of Filipino ancestry, and then compare that to Senate votes for independence in the Tydings-McDuffie Act of 1934 (which granted the Philippines self-government, later to become independence). You could do this with House votes on that bill too, but absent data on milk, sugar cane, etc. by congressional district, the results will not be particularly helpful.

I’ve transformed sugar beet/cane production, cotton production, and milk production to an approximately logarithmic scale. The maps show that sugar beet and cotton production, taken together, unite most of the West with the South, and this is where most of the votes in favor of independence come from.

Let’s look at this more formally. The dependent variable is the number of Senate votes in a state (0, 1, or 2). The independent variables are the (transformed) variables above, along with a measure of partisanship in each state’s senate delegation. I estimate an ordered logistic regression, with the results below.

DV: Senate Votes for Philippine Independence in 1934, by State

Variable Estimate S.E. t value cotton 0.3725 0.2049 1.818 sugar beets 0.3652 0.2071 1.763 sugar cane 6.4251 2.410e-07 2.666e+07 milk -0.1963 0.3147 -0.6237 filipinos 1908.9278 6.972e-04 2.738e+06 democrat 3.0975 1.231 2.516

These results support the idea that cotton and sugar beet lobbies mattered; not so much support for the dairy lobby. The huge, highly statistically significant coefficients on “sugar cane” and “filipinos” represent the fact that Louisiana (which produced the overwhelming majority of sugar cane) and California (which had the overwhelming majority of Filipinos) voted for independence.

The question that this does not answer is why the U.S. did not grant independence to Puerto Rico or Hawaii at the same time. Both of these territories exported tremendous amounts of sugar to the U.S., so my argument would expect that there would be a demand to get them out of the U.S. too. There was an attempt to do so with Puerto Rico in the late 1930s (led by many of the same people), but it seems to have failed, and there was no vote on it. I’m unaware of any similar move for Hawaii.

Any thoughts on this would be welcome. My hunch is that it has to do with the interaction of the structure of the Filipino sugar industry and the addition of copra as a main export from the Philippines. Puerto Rican and Hawaiian sugar plantations were owned mainly by Americans (contrast that to the majority indigenous Filipino sugar industry) and the other export products produced in PR and Hawaii (coffee and pineapples, respectively) did not compete with anything produced in the U.S. mainland. Input from the world’s leading authority of the expansion of the states westward in the 1800s would be most appreciated.