As President Barack Obama heads to Trinidad and Tobago to meet with leaders from the hemisphere, Cuba must be on his mind. He has slightly, very slightly, eased some of the conditions of the 47-year-old embargo on the island nation–less than many Americans wanted, and more than the hardest of the hardliners wanted.

His temerity is a testament to what a problem Cuba has now become for the United States. Once it was a political problem, involving the vote of Cuban-Americans in Miami. But as the generation that fled Fidel Castro’s revolution all those years ago has declined in numbers and influence, the epicenter of the Cuban problem has moved north from Miami to Washington.

Successive administrations have wrestled with what to do about Cuba; how to satisfy the angry refugees in Miami and to begin to normalize relations with our closest neighbor after Canada and Mexico. At one time, it was necessary to punish the communist regime for its willingness to be an outpost of the Soviet Union and a base for its missiles, and a fomenter of revolution in Africa and South America.

But things change, even in long-running dictatorships. No longer can Castro or his brother Raul, who has succeeded him in the day-to-day running of Cuba, look to Russia for succor, nor thrill to the applause of the unaligned nations.

The Brothers Castro–old, old men–have long since drawn in their international horns and have tacitly admitted the failure of their glorious revolution by tentatively loosening some of the economic reins (small private restaurants, foreign-currency accounts and cell phone ownership) that so enslaved Cubans. Last time I was in Cuba some party officials, over rum, told me that much of the old apparatus of the state–like the block informers—had become rusty.

Nowadays, Cubans seem a lot more concerned with the limits of their failed economy than the oppressive nature of the state. When I visited Cuba in the mid-1980s, the sense of the state was everywhere and was oppressive. You got the feeling that that if a group of people were walking down the street, they would all strive to be in the middle–not in front and not behind. In those days, the Russian presence was palpable and depressive.

As in the Soviet Union itself, government officials kept to the party line. Twenty years later, these same officials made jokes about the communist party and the governing apparatus. Particularly, I found them happy to ridicule the myth of Che Guevara, the mythological Argentine doctor who fought alongside Fidel Castro.

In short American attitudes to Cuba are changing as Cuban attitudes toward themselves are also changing. Theirs is not a yearning for political freedom as for personal mobility. Imagine growing up 90 miles from Miami, listening to commercial radio from Florida and knowing that if things do not change, your future will be one of poverty and confinement? Your face forever pressed against the American windowpane.

A government official, a member of the Communist Party, told me: “We are tired of rice and beans. We can smell the pork. We want some of it on our plates now.” A colleague of this man said that in the time of the Soviet Union, he would not have dared to speak up the way he did, but now it did not matter.

Obama has shown caution–as he does in many things–in edging towards a greater liberalism with Cuba. His challenge is geographic as well as political. If an open society emerges in Cuba, untold numbers of Cuba’s population of 11 million will try to emigrate to the United States. On Florida’s East Coast, thousands of boats are ready to illegally bring Cubans to the United States; likewise aircraft.

Cuba has no great wealth beyond its people; its biggest export is still sugar. Its people long for American goods, but they are penniless. U.S. agricultural exporters yearn to increase sales to Cuba, but the market is small.

There are already about 200,000 Americans who visit Cuba every year, according to the U.S. Interest Section in Havana (an embassy in all but name).

As the end of days for the Castro regime looms in Havana, a crisis grows in Washington: How will we keep the Cubans in Cuba if a new government meets all the well-published conditions for ending the embargo? A few Americans will head to Cuba. But mucho Cubans will be Miami-bound–like hundreds of thousands almost immediately. You cannot build a fence down the coast of Florida.