Suppose for a moment that the seven members of the US Congressional Black Caucus who visited Havana some days ago had become hungry somewhere between their four hours with President Raúl Castro and their mercifully shorter rendezvous with his brother Fidel. They might have taken the guidebook and looked for a good paladar, or small private restaurant, where they could continue to gush about Fidel's sense of humour and Raúl's kindness over lobster or pork.

Say it was Frommers guidebook, and they were attracted to the description of El Hurón Azul, on the Calle Humboldt, not far from the Havana Libre Hotel - “a calm and elegant joint” featuring “beautiful paintings by prominent local artists”. They might have asked the hotel receptionist to call 879-1691 and get a reservation, since private restaurants are restricted to 12 place settings.

They might have asked but they wouldn't have got, because just before Christmas El Hurón Azul was closed down by the authorities. Thoughtfully the Cuban rozzería posted a slideshow detailing all the terrible things they found on the premises of the chap who ran the paladar - a slideshow that told the viewer far more about them than about the filthy capitalist they'd nicked. There were photos of incriminating racks of wine, of medium-sized refrigerators half-full of food, of pictures (including, bizarrely, a framed print of the Mona Lisa, which even the Cuban police cannot have believed was the original) and other items suggesting to an envious citizen that the entrepreneur had been making a little bit of money out of his enterprise. Success like that, it was implied, had to be punished.

I owe this tale to a blogger, but one quite unlike those that have made headlines here in recent days. Yoani Sánchez is a 33-year-old resident of Havana, and her Generación Y blog (available in translation on desdecuba.com/ generationy/) gently tells the story of her life and thoughts, her harassment by the authorities, the police spies downstairs, the continued non-functioning of the Russian elevator up to her eighth-floor apartment and the continued non-functioning of the economic and political system of her native island.

Her blog is blocked in Cuba (I know, I tried) and she “blogs blind”, posing as a tourist to send e-mails and photos to friends abroad from hotel computers. She's funny, honest and low-key, believing that aggressive language and defamation “only exacerbates the cycle of intolerance that is an obstacle to reasoned debate”. Amen to that.

Sánchez has won several international awards in the past 18 months but has been forbidden permission to travel abroad to receive them. Fidel even mentioned her slightingly in one of his interminable Reflections for the party newspaper, Granma, expressing disappointment that a youth of Cuba should accept questionable foreign awards. Her husband, in his blog, hit back by listing some of those worthies who had received the Order of José Martí at the hands of the Great Reflector: Brezhnev, Mugabe, Mengistu, Ceausescu and Erich Honecker among them.

Sánchez concluded her piece on Hurón Azul by saying she was “deeply shamed that the police in my country are dedicated to imprisoning enterprising citizens, while the streets are full of criminals who snatch purses, steal and defraud”. The lesson seemed to be “that in order to prosper one must get off this island”.

The point is that economic collapse and politics are linked in Cuba. The chronic lack of employment, ubiquitous black market, street touting and theft from the State arises from an ideological objection to private enterprise and a commitment to its suppression (except where unavoidable, as in the tourist industry). Though the Castros have occasionally liberalised a bit here or there, those new dawns have always been turned out to be false.

The lack of private autonomy in the economic sphere is matched in the political one. The system is ossified and ideologically dead. There is a kind of inert acceptance of some of its passive virtues, but none for its activist and reforming rhetoric. The billboard slogans, so attractive to Westerners, are ignored by Cubans.

There is no free press, no alternative press, no non-government TV or radio, no unblocked internet, and any attempt at organised opposition is met with harassment (including of family members), arrests and imprisonment. More than 50 of the 75 activists arrested six years ago, ostensibly as “mercenaries” but in fact for organising a petition, still languish in prison, often in ill health.

Depressingly you can still find plenty of academics and journalists in Britain - Fanonites, sugar-cane romantics and serial Third World guilt-trippers - to defend the rule of the Brothers. But in Cuba itself what has helped hold the thing together is the Yanqui threat: it is the Americans who cause shortages by their embargo, it is the Americans who create the security crisis that necessitates heavy policing.

How will this play now that we are entering the Obamanian New World? Yesterday President Obama announced the lifting of travel and remittance restrictions on Cuban American citizens. The practical effects will be an increase in US tourism visits to relatives on the island, and an increase in US money going directly to some lucky Cubans. Congress is also looking to end other restrictions, particularly hoping to get US grain sold to Cuba.

The calculation, as with other countries, such as Iran, may be that this will lead to better political relationships, a softening of hostilities and, over time, liberalisation in Cuba itself. But will it? It might instead give the Castros enough American money to buy themselves another period of revolutionary torpor. My reading is that the men in Havana badly want to avoid change, and are convinced that reform will mean the end of their 50-year experiment.

But they are not always going to be masters of their own destinies. Yoani Sánchez may have been overoptimistic when she wrote last week that she didn't see anyone on the streets who worried about a better relationship with the US. “The nervousness is only among those who have used the confrontation to stay in power. Rather, I observe the joy, the hope, the slight impression that the distance between Miami and Havana might become smaller and more familiar.”

We can really help to shrink the distance by ensuring that our dialogue with Cuba includes people such as Yoani Sánchez and those Cubans, like her, campaigning for democracy, liberty - and the right to own Mona Lisa prints.

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