I have been trying, for some time now, to circle an issue that we can consider to be a cousin of the emerging “state capacity” literature (see Mark Koyama’s amazing summary here). This cousin is the literature on “empire effects” (here and here for examples).
The core of the “empire effect” claim is that empires provide global order which we can consider as a public good. A colorful image would be the British Navy roaming the seas in the 19th century which meant increased protection for trade. This is why it is a parent of the state capacity argument in the sense that the latter concept refers (broadly) to the ability of a state to administer the realm within its boundaries. The empire effect is merely the extension of these boundaries.
I still have reservations about the nuances/limitations of state capacity as an argument to explain economic growth. After all, the true question is not how states consolidate, but how they create constraints on rulers to not abuse the consolidated powers (which in turn generates room for growth). But, it is easy to heavily question its parent: the empire effect.
This is what I am trying to do in a recent paper on the effects of empire on shipping productivity between 1760 and 1860.
Shipping is one of the industry that is most likely to be affected by large empires – positively or negatively. Indeed, the argument for empire effects is that they protect trade. As such, the British navy in the 19th century protected trade and probably helped the shipping industry become more productive. But, achieving empire comes at a cost. For example, the British navy needed to grow very large in size and it had to employ inputs from the private sector thus crowding-it out. In a way, if a security effect from empire emerged as a benefit, there must have been a cost. The cost we wish to highlight is the crowding-out one.
In the paper (written with Jari Eloranta of Appalachian State University and Vadim Kufenko of University of Hohenheim), I argue that, using the productivity of the Canadian shipping industry which was protected by the British Navy, the security effect from a large navy was smaller than the crowding-out from high-levels of expenditures on the navy.
While it is still a working paper which we are trying to expand and improve, our point is that what allowed the productivity of the Canadian shipping industry (which was protected by Britain) to soar was that the British Navy grew smaller in absolute terms. While the growth of the relative strength of the British Navy did bolster productivity in some of our tests, the fact that the navy was much smaller was the “thing in the mix that did the trick”. In other words, the empire effect is just the effect of a ramping-down in military being presented as something else than it truly is (at least partly).
That’s our core point. We are still trying to improve it and (as such) comments are welcomed.
Notes On Liberty 
US Largest consumer of natural products,
This is an extremely interesting point, the worth of fighting pirates and guerre de course seems difficult but is completely worth the effort. Strangely, just before reading this post, I finished the book “To Rule The Waves” by Arthur Herman (https://www.amazon.com/Rule-Waves-British-Shaped-Modern/dp/0060534257), which asserts that the rise of large-scale trade went hand in hand with the growth of British naval strength, and points very specifically to the 18th and 19th centuries. On page 402, he asserts that it was only naval protection that enabled British trade to grow considerably during the Napoleonic wars (over 11,000 British merchants were captured by the French from 1793-1815 and far more would have been but for the British blockades and convoy protection). How much can one measure the cost-to-yield of maintaining peaceful trade against such depredation?
Herman also argues that Naval research and technology drove the development of far better seagoing technologies without which large-scale merchant ventures would have had far lower yield (perhaps the most famous example is the Longitude Prize) and the demand for iron and ship production was a major driver of the early Industrial Revolution. While I think that both of these arguments are very vulnerable to crowding out arguments, it seems to me that there were nuanced interconnections between technology, trade, and naval power that each had positive feedback into the others. It seems to me that by examining the very large investment made by the British East India Company in their merchant marine in this very period gives a parallel in which private interests made similar investments in protection of sea trade routes, showing its probable positive return on investment.
I am glad to see that you have recognized that naval production was almost always based on relative strengths of navies. The huge decomissioning trends of the mid-19th century in Britain was exceeded by that of their enemies/rivals (the Dutch had been weak since the late 1600s, the French were exhausted completely, and the Spanish and Portuguese were on a long decline worsened by French occupation). However, there is one major aspect to consider in examining naval strength longitudinally: complete revolution in ship technology. Steam, iron plating, and amazing advances in artillery picked up hugely after 1815, and the British navy in the Crimean War would have been unrecognizable to Nelson. I am not sure how this would affect your analysis, because navies became simultaneously more expensive and more effective, and GDP was exploding fast enough to support such high-tech advances without bankrupting the Brits. I am sure this is not an original problem, but I am interested in seeing how historical economists can control for such changes.
Good luck on this paper, it seems like an extremely useful examination with a lot of interesting complications and a fundamentally important commentary on the balance between maintaining law and allowing market determination of resource distribution.
[…] This is from my fellow Notewriter Kevin on another fellow Notewriter’s (Vincent) recent post about shipping and imperial navies. […]