Paul Kramer is an associate professor of history at Vanderbilt University and the author of “The Blood of Government: Race, Empire, the United States and the Philippines” (University of North Carolina Press, 2006). He also wrote the article “The Water Cure,” which ran in the February 28, 2008, issue of the magazine.

It was 1935, and the Guantánamo naval base had to go. So declared an American commission stocked with foreign-policy experts: the United States was pursuing less antagonistic relations with its southern neighbors, and an American base on Cuban soil, anchored by a lease without an end date, looked increasingly like an “anomaly.” Weren’t there enough defensible harbors on the United States’ own Gulf Coast, or on Puerto Rico? The commission wrote that the U.S. government should “seriously consider whether the retention of Guantánamo will not cost more in political misunderstanding than it is worth in military strategy.”

Where was the base? This was a trickier question than might first appear. It straddled both sides of lower Guantánamo Bay, roughly five hundred miles east and south of Havana, about as far from the capital as one could travel and remain in Cuba. The bay opened onto the Windward Passage, one of the hemisphere’s most trafficked sea-lanes, linking the Eastern Seaboard to the Gulf of Mexico, Central and South America, and, through the Panama Canal, the Pacific Ocean. In 1899, an American military planner, stressing the need for naval bases and coaling stations in Cuba, had called the island “an outer bar of the Mississippi.”

The terrain that rose above the bay—dry, sun-blasted hills, where cactus and scrub clung to outcroppings of barren rock—was hostile enough that Cuba’s Spanish rulers had taken their time colonizing the region. For centuries, Guantánamo had effectively been no state’s domain, a haven for pirates and slaves escaping both Cuba and Haiti, only a hundred miles across the Windward Passage at its nearest point. For them, Guantánamo had meant something like freedom....