The Birth of the American Empire

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In 1963, famed meteorologist Edward Lorenz published a groundbreaking paper. In it, he advanced the theory that when a seagull flaps its wings, it sets in motion a a change of events which can lead to thunderstorms, tornadoes and hurricanes. This was the butterfly effect. Today Lorenz’s theories are controversial in the scientific community, but have found a new home in the study of history. For more often than not, the greatest events trace their roots back to the smallest anomalies. This is the story of how America built an empire, simply because they were desperate to obtain Guano, bird waste.

Guano is bird excrement that has been dried and compacted over hundreds of years into powdery deposits. It is produced primarily by seabirds, and is largely found on rocky islands. Rich in nitrogen, guano is an excellent fertiliser. Indeed, its usefulness has been long known, with Spanish colonial documents suggesting that the rulers of the Inca Empire guarded it closely, administering the death penalty to anyone who disturbed the seabirds that produced it. However, it was not widely used until the beginning of the 1840s.

By the early 19th century there was an impending agricultural crisis, triggered by the widespread abandonment of crop-rotation. It was at this time of panic that Malthus remarked “the power of the population is so superior to the power in the earth to produce sustenance for man, that premature death must in some shape or other visit the human race.” It is in this dire context that the miraculous capabilities of guano became universally recognised, and soon farmers and their governments were desperate to get their hands on it. In 1844 Peru became the first country to receive a large shipment of guano, which weighed 700 tonnes. Soon Peru nationalised it, and made guano an exclusive resource of the state. Realising the usefulness of the fertiliser, Peru restricted the sale of guano to foreign nations. As supply was limited, and demand feverish, the price of guano was exorbitant.

American farmers, possessing an abundance of land but no effective way to cultivate it, applied huge pressure on their government to obtain its own supply of affordable guano. The government responded with the Guano Islands Act of 1856, introduced by W.H. Seward, that stated “whenever any citizen of the United States discovers a deposit of guano on any island…not within the lawful jurisdiction of any other government and not occupied by the citizens of any other government and takes peaceable possession thereof…the island will be considered as appertaining to the United States.”

The lack of a clear meaning of the word “appertaining” would allow America to expand its empire in a subtle and highly astute manner. For while most empires aim to acquire direct control over key regions, US imperialism carried out what Burnett calls “boundary management.” In this process the US sometimes limits its own power, but only in ways that are advantageous, as shall be seen later. For now, however, the statement that “nothing in this act contained shall be construed on the United States to retain possession of these islands” reveals the reluctance to completely annex a territory that is distinctive of US imperialism.

By 1863, the US had annexed 59 guano islands under the Guano Islands Act, but this had not been without controversy. In 1857, Navassa Island was found to have promising guano deposits and as such the US swiftly transferred the island to a family called the Coopers who had discovered it. However, Haiti claimed that the island was under its “lawful jurisdiction”, and sent a flotilla to reclaim the island, provoking a response from the US navy to protect its citizens. Haiti withdrew without conflict, but refused to declare the legitimacy of the US occupation. This meant that confusion remained, and no one could say definitively what status guano islands had in relation to the US. Navassa was, paradoxically, part of the American empire, but not part of the United States of America.

To try and clarify this confusion, Jeremiah S. Black set out a list of conditions that had to be met for the legal acquisition of a guano island. However, this prompted bureaucratic chaos, and, effectively wearied into submission, Black and the US government simply decided to accept any new “appurtenances.” Yet in an episode of Baldrickian incompetence, this decision was not made public. The US government still had not clairified the status of the guano islands, which suited them perfectly, as the country could continue to acquire greater influence over the islands, without encountering the problems that direct control would pose. 

Manual labour was required to extract guano deposits (the noise of the machines frightened away the birds) from the oppressively hot and dry islands. Guano mining was, as Immerwahr puts it, perhaps the “worst job of the 19th century.” The stench was horrific, inhaling guano dust caused serious damage to the lungs, and living space on the islands was cramped.

The Peruvians had relied on the Labour of kidnapped Chinese nationals, and American guano entrepreneurs enlisted the labour of Hawaiian workers, promising them beautiful women and exotic fruits. The workers instead were confronted with hellich conditions, while they often found the contracts they had signed meant very different things in Hawaiian and English. One such Hawaiian, Kailiopio, wrote “the work rules of ours are just not true.” It is unsurprising then that there were often brawls between white guano island supervisors and the unfortunate workers. One such brawl escalated to a full uprising on the island of Navassa.

On 4 September 1889, an oppressed worker struck a supervisor named Roby with a metal bar. In the ensuing violence, five of the island’s supervisors were murdered. One month after this riot, the USS Galena collected the occupants of Navassa Island to return them to the US. On the voyage back, the Baltimore attorney Hayes identified eighteen workers as instigators of the violence, and seven of them were later charged with murder.

Yet the worker’s plight evoked sympathy from the public, and they received support from the “Grand Order of Galilean Fishermen”, and employed as their defence lawyer one E.J. Waring, who was the first African American to pass the Maryland bar. The case was named “Jones vs the United States of America” and it would supposedly force the judicial system and government to finally give some sort of binding definition as to what the status of guano islands was, and clarify what “appertaining” actually meant. 

The defence of the workers was that the “peculiar species of discovery” of the Guano Islands Act had no sanction in international law or Congress, and that subsequently the federal court had no jurisdiction over Navassa Island. For land to be legally acquired under international law it had to be obtained under one of four conditions: “occupancy, cession, conquest, (or) discovery”. The Guano islands clearly had not been acquired through conquest, cession or occupancy (because occupancy was temporary) and could only have been legally acquired through discovery.

However, the defence claimed that the discovery of new territory had to be permanent and not just temporary, and that guano islands came under the latter category because they were abandoned once their guano supplies had been depleted. No permanent settlement existed on any of the islands. Consequently, the guano islands did not belong to the US, and so the workers could not be punished for any crimes committed there. Importantly, the defence also attacked the infamous “appertaining”, saying “it is respectfully inquired what is the significance or meaning of this desultory phrase.”

In theory, the Supreme Court should have been obliged to clarify. Yet the Court effectively dodged this crucial question by ruling that the Act was “constitutional and valid.” This was based on the fact that the title of newly acquired land is not bestowed upon individuals but the US. Therefore, due to skilful manoeuvring, the Guano Islands Act was still not clarified, and the US was not committed to any specific policy or obligations concerning new territory, meaning they could expand their influence at their discretion.

In the aftermath of the trial, three of the defendants were found guilty of murder, but their original death sentence was commuted to life imprisonment by President Harrison. He was moved by the evidently poor treatment of workers and declared that “it is inexcusable that US labourers should be left within our own jurisdiction without access to any government official or tribunal for their protection.”

Due to the Supreme Court’s obfuscation regrading the legal status of the territory, the issue re-emerged at the end of the 19th century. Following the Spanish-American war, the US annexed the territories of Guam, Puerto Rico and the Philippines. In the subsequent legal proceedings, which are collectively known as the “Insular Cases”, the Supreme Court was forced to define the relation of these new lands to the United States. Whilst there was little pressure demanding clarification over some barren rocks in the Atlantic, the matter of key islands gained in warfare was another matter. The descision of the Court would have ramifications for millions of people.

The most notable of the “Insular Cases” was “Downes vs Bidwell” which concerned the status of Puerto Rico. It was at this moment that it was finally revealed in the judges’ speeches what the US considered its relationship with newly acquired territories to be. Consequently, we can finally assess the lasting impact of the Guano Islands Act. Justice White used “appertaining” to argue that the new territories “belonged to” but were not “part of” the United States. White attempted to clarify this by saying that “whilst in an international sense Puerto Rico was not a foreign country…it was foreign to the US in a domestic sense because the island had not been incorporated into the US.”

At first this seems to be an unnecessary complication, but it was a complication to the United States’ advantage. Since it was a large and powerful country, many new territories wanted to be incorporated into the US in order to obtain citizenship. However, this was not desirable to the US because they did not want the responsibilities of looking after foreign citizens.

As we have seen, this responsibility could lead to great controversy, such as uprisings or diplomatic disputes, while at the same time mass enfracnchisements were rarely domestically popular. Indeed, when the Guano Island Acts was first passed, Senator Clayton was deeply concerned that dealing directly with foreign peoples “would involve us in a great deal of trouble.” Direct control would also invite competition with other empires. The US had found a way to gain the economic, military and political advantages of imperialism, without the burden of the strategic and legal complexities full annexation brought. When it came to empire, the US wanted to have its cake and eat it.

Therefore, the US passed vague legislation like the Guano Islands Act to ensure that “acquired territory, in the absence of agreement to the contrary, will bear such relation to the acquiring government as may be by it determined.” In other words, the US could set its own limitations on its power in order to obtain the greatest degree of influence over new territory with the least risk. The limitations themselves were set by providing very specific instances in which direct US intervention in a country would be taken, and so the US could exert control while disclaiming sovereignty. It is for this purpose that the perplexing phrase “appertaining” was used in the Guano Islands Act of 1856. As was noted by the defence of the Navassa Island workers, the word “appertaining” carries “no exact meaning and lends itself readily to the circumstances and wishes of those using it.”

Therefore, the United States could refer to it in territorial disputes and declare whatever meaning for the word that best fit their aims; this was exactly what the Supreme Court judges did in “Jones vs the United States”. Behind the protective barrier of confusion caused by the meaning of one unusual word, the United States annexed territory, then assigned to it the most convenient status. The Guano Islands Act remained perplexing and in 1931 a US State Department report said that it was “difficult to determine the exact legal significance of acts performed under the Guano Act.”

 However, the State Department also argued the Guano Islands were “barren outcroppings of rock, possessing no value save their deposits.” This assertion was simply not true. The hundred or so islands annexed by the US in the 19th century had great strategic use for the United States during the Second World War and in peace time provided easy access to trade routes like the Panama Canal.

Yet, the most important consequence of the Guano Islands Act was how it defined US imperialism. This was a method that was as tentative as it was assertive, and as restrictive as it was freeing. The goal was not to acquire as much territory as possible but to carefully manage the boundaries of the American Empire, whether this required expansion or restriction. Once the United Statess had filled in the map from coast to coast, pencilling in island chains as American territories meant little. Instead, the US government concerned itself with acquiring ever greater influence. The Guano Islands Act was used more to qualify and restrict US expansion through subtle legal distinctions than to dominate other countries. 

Its significance in the history of US imperialism is often overlooked, as it does not fit the traditional imperialist narrative, but the Guano Islands Act provided an assurance and flexibility that meant the US could expand or limit its empire on a whim. The precedent established with guano islands would be the template which the US would go on to use as it expanded its power, and from there become the dominant world power. This new model of imperialism, based on legal ambiguity, economic value and the expansion of “influence” as opposed to the expansion of borders through annexation has only grown in popularity in the last century and a half. Indeed, it could be argued that modern great power politics began in 1856, when the US declared ownership of islands full of bird excrement.


Burnett, C., 2005. The Edges of Empire and the Limits of Sovereignty: American Guano Islands. John Hopkins University Press

Immerwahr, D., 2019. How to Hide an Empire: Short History of the Greater United States. Vintage

James, C., 2012. Buried in Guano: Race, Labour and Sustainability. Oxford University Press

Rosenthal, G., 2012. Life in Labour in a Seabird Colony: Hawaiian Guano Workers. Oxford University Press

https://www.jstor.org/stable/40068316?Search=yes&resultItemClick=true&searchText=Guano+act&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3DGuano%2Bact%26so%3Drel&ab_segments=0%2Fbasic_search_gsv2%2Fcontrol&refreqid=fastly-default%3A22c623a1fb7f01fcb4aaa622755c80eb