Final answer:
Yellow fever severely weakened Napoleon's army during his attempt to suppress the Haitian revolution, leading to his withdrawal and the sale of the Louisiana Territory to the U.S. This and other military difficulties contributed to the decline of Napoleon's empire.
Step-by-step explanation:
Effects of Yellow Fever on Napoleon's Campaign in Haiti
The yellow fever epidemic had a devastating impact on Napoleon Bonaparte's forces during his campaign to suppress the Haitian revolution. In 1802, Napoleon dispatched an army of 40,000 troops to Hispaniola to quell the slave uprising. However, yellow fever ravaged his army, with many soldiers succumbing to the disease. This forced Napoleon to abandon his efforts in the New World and ultimately led to the sale of the Louisiana Territory to the United States in 1803 for $15 million. The loss of his troops to tropical illnesses and his subsequent military campaigns, particularly the disastrous invasion of Russia, undermined Napoleon's position and contributed to the eventual collapse of his empire.
The failure in Haiti due to yellow fever, along with other issues such as the prolonged conflict in Spain, referred to as 'Napoleon's Spanish ulcer,' and the extensive losses during the Russian campaign, demonstrated to the world that Napoleon was not the invincible military leader he was once perceived to be. The disease thus had indirect but significant effects on the broader geopolitical situation, reshaping the history of the Americas and Europe.