Cuba’s keenness on outside investment stems from the second reason to reconsider the embargo. The regime’s fortunes are tied to those of Venezuela, which supplies Cuba with cheap oil in return for doctors, intelligence support and a splash of ideological credibility. But Venezuela’s economy is crumbling and its leftist government is in trouble, so Cuba needs a plan B in case it demands market prices for its oil. The choice is probably between another helpful oil producer (Russia, whisper some) and greater trade with the outside world. Small cracks in the embargo allowed $360m of exports from the United States to Cuba in 2013; that figure would zoom if restrictions were lifted. Would Congress really prefer the Castros to choose someone like Vladimir Putin over free enterprise?