Trump's move in the narco state formerly known as Maduroland is the nexus of several threads and possibilities.

With this one move, the Trump administration has turned the screws on at least a half a dozen global troublemaking regimes. - Michael Smith

1. Cuba is like Obamacare, it needs massive subsidies to survive. We are now in the FO part of the FA.
2. Russia needs oil prices to stay up, when Venezuela's very productive fields come back online (Chavez destroyed their exploration, production, and refinery capacities after kicking out the people who knew how to manage those aspects), oil prices could drop to $50 a bbl (US producers can still make money at around $35 a barrel). That means less revenue to the Russian government - and that means less money to fund Ukraine operations.
3. Iran is watching and in the middle of massive protests. This could be the Iranian people's moment for their own regime change.
4. China has massive investments in South America - mostly in countries they prop up, so this has to have their attention.
5. The US's new use of direct action when the talk runs out has the narcos attention as well. Maybe even Mexico is paying attention now...