“It’s complicated,” said David L. Goldwyn, who was a top State Department energy envoy in the Obama administration.

“Tough sanctions could lead to a default on their bonds and a collapse of internal investment and oil production,” he added. “Other impacts could include civil unrest, refugee flows across their borders, and a cutoff of Venezuelan financial support to Cuba and Haiti that could lead to migration flows to the United States.”

There is also the potential for collateral damage to the United States.

Any trade embargo could raise gasoline prices, cost jobs in the oil patch and dampen profits for several major refiners. A decrease in Venezuelan exports could raise global oil prices, bolstering the economies of Russia and Iran just as Washington prepares to ratchet up sanctions on those countries.

In briefings, administration officials would not speculate on what would come next, but they emphasized a menu of options. Mr. Trump, in a statement last week, said “the United States will not stand by as Venezuela crumbles.”

The immediate concern is over Mr. Maduro’s plan to hold an election this weekend for a Constituent Assembly that would circumvent the opposition-controlled Congress and write a new constitution. The new assembly, which is devised to be dominated by groups that support the regime, would presumably consolidate more control in the hands of the president.

The escalating street violence and hunger in Venezuela are threatening to spread. Tens of thousands of Venezuelans have already fled the country, heightening social pressures. The country’s plummeting economy has added pressure on a region struggling with low commodity prices.

For now, the United States is treading cautiously in its approach to Venezuela.

As a first step, the administration this week froze assets of, and instituted a ban on travel visas for, 13 influential Venezuelans including electoral, military and correctional officials. One of them is Simón Zerpa, vice president for finance at Petróleos de Venezuela, known as Pdvsa, which could complicate relations between the state oil company and American players in Venezuela that are already struggling to get paid for services. The move follows similar sanctions imposed by the Trump administration on Venezuela’s vice president, Tareck El Aissami, and eight members of its Supreme Court.