The Lousiana Purchase: How Yellow Fever and Swiss Anarchy doubled America Overnight

On this day in 1803, the United States of America doubled in size when the United States government bought the vast territory of Louisiana from the French government of Napoleon Bonaparte for a derisory sum.

Napoleon, who expended hundreds of thousands of French and allied lives for relatively minor territorial gains in Europe, gave away a territory vaster than Western Europe with a mere flick of a pen.

There is something about this which doesn’t quite add up. So, what in fact happened? Why did Napoleon, usually regarded as a genius, do something that so obviously lessened French power and prestige?

The obvious answer, given the general strategic position of French land power and British sea power in the Napoleonic Period, is that Napoleon made a strategic retreat from the New World. 

But while there is some truth in that view, there are a few problems. Firstly, the Purchase happened while Britain and France were at peace, and, secondly, France continued to maintain other colonies in the New World, most notably on the island of Guadeloupe which was held until the British captured it in 1810.

The real decider were events on the Caribbean island of Hispaniola and in the Helvetic Republic, a Swiss state that Britain believed should be independent of French control.

Hispaniola, the island now occupied by the states of Haiti and the Dominican Republic, was the site of the main and most profitable French colony in the New World, Saint-Domingue. Following the French Revolution the position of Blacks had gradually improved as Whites fought among themselves – Royalists vs. Republicans. As the island moved through cycles of anarchy and diminishing returns to order, the Blacks and Mulattos gained increasing power.

Toussaint Louverture

After some political jockeying, the ex-slave Toussaint Louverture had established himself as the dominant leader of what was still technically French Saint-Domingue. 

While making secret treaties with the British, Louverture still presented himself as a "loyal" Governor General for France. But back in France, Napoleon had big plans for the French Empire in the New World and they certainly did not involve the ex-slave.

By the Third Treaty of San Ildefonso (1800) France had reacquired the Louisiana Territory from Spain, but the keystone to Napoleon’s North American Empire was still to be the colony of Saint-Domingue, its historical economic powerhouse. 

After consulting with French planters, Napoleon, whose wife also happened to be from former a slave-owning family, decided that to make the project economically viable he would have to depose the new Black political class that had risen up in the revolutionary period, and reimpose slavery. With this intention, he sent a fleet and army under his brother-in-law, General Charles Emmanuel Leclerc to seize the island.

Arriving in February 1802 and using a mixture of force, diplomacy, and guile, the expeditionary force gained control of the island and captured Louverture, but they were unable to maintain order and faced continued opposition from forces on the island, led by the new Black leader Dessalines. 

French troops also suffered much from various tropical diseases, including Yellow Fever.

Napoleon was never one to fix on just one plan or objective. Much of his success as a general and diplomat was due to his ability to always have alternate plans, and thus confuse the enemy as to his real intentions. While he was clearly interested in establishing a strong overseas empire – it is said that around 80,000 troops were sent to Hispaniola – he also had alternative and even contradictory plans, including an invasion of Britain, which, of course, if successful would have bolstered his colonial plans.

Napoleon intervening in Switzerland.

With little progress being made in Hispaniola, relations with Britain therefore became more important. 

But here the focus was not on the sultry Caribbean, but instead on the Alpine valleys of Switzerland. 

According to the Treaty of Lunéville (1801) and the Peace of Amiens (1802), the Swiss "Helvetic Republic" was supposed to be an independent state. But an internal conflict between Centralists and Federalists caused the country to collapse into anarchy, giving  Napoleon an excuse to reoccupy the country. 

This move greatly angered Britain, as it underlined rising French dominance of the European continent and increased the possibility of Britain being excluded from European markets. 

Of course, if Napoleon had had positive prospects in the New World, it would have been worth his while to come to an agreement with Britain over Switzerland, as Britain dominated the Seas. However, the negative situation in Hispaniola precluded this, so he decided to focus once again on dominance in Europe and France's traditional enmity with Britain. 

This prepared the way for Jeffereson’s triumph, which could be put down to the stubborn resistance of the Blacks on Hispaniola, the Yellow Fever that decimated the French troops in the island, and the anarchy of the Swiss, which led to growing tensions between Britain and France.

Presumably Napoleon sold Louisiana so cheaply because he believed it would be temporary. He perhaps thought that defeating Britain would lead to a "renegotiation" of the Louisiana Purchase and the reestablishment of a French North American Empire that would include not only Hispaniola and Louisiana, but also Canada. Britain’s subsequent defeat of Napoleon therefore benefited no country more than America.