A British journalist compared the huge U.S. delegation that accompanied U.S. President Barack Obama on his first visit to Havana to Japanese soldiers stumbling out of the jungle to discover that the war ended a generation ago. And the Rolling Stones, who are staging a free concert for half a million people in the Cuban capital on Friday, explained that Obama was their opening act.

The U.S. embassy in Havana has already reopened, but only Congress can end the U.S. trade embargo against Cuba. Under Republican control, Congress is not going to do that, so this visit was really just a social call.

Yet no journalist can resist speculating about whether this opening portends great political changes in Cuba, maybe even the eventual end of the long dictatorship of the Castro brothers and the Cuban Communist Party. Least of all me, as I have long been speculating about that. I never went to Cuba during the "heroic" years when the leadership lived in permanent fear of American invasion or subversion, and most Cubans really were ready to fight to defend the revolution. My first visit was in the mid-1980s, when the bloom was already off the revolutionary rose.