He's almost 17 now, a strapping young man with cropped hair, studying to be an officer at a military school in Havana. But exactly 10 years ago, Elian Gonzalez came home as the most famous little boy in the world, a pawn in a wrenching international custody battle that some say cost Al Gore the presidency.

The affair began on Thanksgiving Day 1999, when a fisherman found Elian floating in an inner tube in the Straits of Florida. He and his mother were part of a group of Cubans trying to escape to the US, but she drowned in the attempt. He was sent to live with relatives in Miami; they wanted to keep him, but his father, who was separated from his mother, wanted Elian back with him in Cuba.

After a months-long tug of war, the Clinton administration, of which Gore was vice-president, ordered that Elian be returned to his father. Cuban-American leaders never forgave Gore, and in November 2000 their hostility could well have cost him the few hundred votes by which he lost Florida and, consequently, the White House.

But in Cuba, the little boy was ordained a national hero. He may not have known much about it at the time, but his case was held to have put one over the giant neighbour to the north, highlighting the iniquitous embargo it had maintained ever since the communists had come to power. According to Ricardo Alarcon, the president of the Cuban parliament, Elian's case had shown Americans "the reality that the imperial propaganda, the industry of deception had tried to hide".

For more than half a century, Washington has maintained its stifling economic and human blockade of Cuba. It has schemed and plotted to get rid of Fidel Castro and his regime. But in vain. President Obama, one can be sure, understands the insanity, and a radical policy shift was widely expected when he came to power. Cuba seemed to be easy, "low-hanging" fruit for a more conciliatory foreign policy that would spruce up the US's reputation in the world. No more would the United Nations General Assembly each year go through the embarrassing ritual of condemning the embargo.

But it hasn't worked out like that. Obama did take some steps to improve relations, by allowing unlimited travel for relatives and expanding telecommunications links. Nonetheless, the embargo is substantially intact. Washington says it can go no further unless Havana does its part too, by increasing the freedoms of its citizens.

Patience with the current state of affairs is running out. Yes, the Cuban émigré lobby that the candidates were so scared to offend in 2000 still exists, concentrated in the important election swing states of Florida and New Jersey. But these days it is not the force it was. A younger generation of Cuban-Americans, born in the US and without their parents' direct experience of the Castro regime, simply does not care as much.

The obvious pluses of a more rational policy now have more political weight – and last week rationalism towards Cuba took an important stride on Capitol Hill, when a House of Representatives committee voted to lift the ban on Americans travelling to Cuba and to remove restrictions on US agricultural exports to the island.

There's still a long way to go: a couple of other House committees, not to mention the full House, must approve the measure, while in the Senate, Bob Menendez, a Democrat from New Jersey and the son of Cuban immigrants, is muttering about a filibuster. But the fact remains that even when George W Bush, who tightened the clampdown on Havana, was in the White House, a cross-party majority on Capitol Hill supported liberalisation to some degree at least. Now, Senate head-counters claim they already have the 60 votes needed to thwart a filibuster.

One by one, the old fallback arguments are crumbling. No one can claim Cuba is a threat to US security or a Caribbean lair for al-Qaeda. But Menendez and his supporters maintain that any easing of restrictions would be a betrayal of Cuba's fragile and persecuted democracy movement.

However, 74 Cuban activists, including current and former political prisoners, have written to every member of Congress, arguing that the bill's benefits to the Cuban people far outweigh any succour it would provide the regime, and that its passage would not be taken as an abandonment of the democratic cause.