The list of delegates includes powerful members of the president’s political movement, including Diosdado Cabello, a top lawmaker in the ruling Socialist Party who was involved in a failed coup attempt in the 1990s, and Cilia Flores, the president’s wife.
But the push to consolidate power also puts the country at a crossroads, one laden with risk.
As Mr. Maduro effectively steers his country toward one-party rule, he sets it on a collision course with the United States, which buys nearly half of Venezuela’s oil. On Wednesday, the Trump administration froze the assets of, and forbade Americans to do business with, 13 Venezuelans close to Mr. Maduro, including his interior minister and heads of the army, police and national guard.
The administration is warning that harsher measures could follow, with “strong and swift economic actions” if the vote happens on Sunday, according to Mr. Trump. In a statement, he called Mr. Maduro a “bad leader who dreams of becoming a dictator.”
There is also the potential powder keg on Venezuela’s streets. Infuriated by Mr. Maduro’s government, the opposition has mobilized more than three months of street protests that have crippled cities with general strikes, rallies and looting. More than 110 people have been killed, many in clashes between the state and armed protesters. Few know how protesters will react to newly imposed rulers.
Even the members of the new assembly themselves are a wild card. Their power will be so vast that they could possibly remove Mr. Maduro from office, some analysts note, ending a presidency that has been deeply unpopular, even among many leftists.
“It’s a crapshoot, a Pandora’s box,” said Alejandro Velasco, a Venezuelan historian at New York University who studies the country’s leftist movements. “You do this and you have so little control over how it plays out.”
Mr. Maduro contends that the government restructuring is necessary to…