In a report published this week, Human Rights Watch and Johns Hopkins University found increased maternal and infant deaths, the unchecked spread of diseases such as measles, diphtheria and tuberculosis and high levels of child malnutrition. Officials know that sanctions will add to hardship, and thus to emigration.

But what else can the Americans do? Mr Trump has repeatedly refused to rule out military action, but a conventional invasion of a country more than twice the size of Iraq, with many armed civilians, would be a massive and risky undertaking. Mr Brownfield suggests that some Venezuelan emigrants could become anti-regime guerrillas, but Colombia’s government would be nervous of that.