According to this, the shipments have already been blocked.
“Two Liberian-flagged, Greek-owned ships that “were en route to Venezuela carrying Iranian fuel, scrapped their deliveries after the U.S. threatened sanctions,” a senior U.S. official told Fox News.”
https://www.foxnews.com/politics/us-disrupts-iranian-fuel-deliveries-venezuela-official-says
America does not need to involve itself directly in an assault on Venezuela. All America has to do is back someone who will. The surrounding countries are being very badly hurt by Maduro. I suspect that the US will give financial. logistics, training and intelligence support. When this is all done, America will probably back either a new Venezuelan regime or Venezuela’s’ incorporation into another country.
Unfortunately, America can probably no longer refine Venezuela’s oil as it is dirty crude and most refiners have retooled to refine fracked light, sweet crude. There are likely no buyers for Venezuela’s oil as it is expensive to refine and the current prices will not support buyers of that oil. So, putting Venezuela back on its feet will take time and probably never pay for itself. In addition, Maduro has stolen and sold most of the country’s other resources, like gold and foreign reserve currencies.
Our nation is dying, here, now. We need to stay out of Venezuela.