Analysis by Candace Piette, BBC Latin America analyst
The Venezuelan opposition have nowhere else to go but the streets and have vowed to keep up their latest month-long campaign of demonstrations across the country.
All their efforts to get an election called early have been frustrated by a Supreme Court and a National Electoral Council dominated by government supporters. Any legislation presented by the Venezuelan Congress, which they dominate, is blocked by the judges.
Opposition leaders say Mr Maduro's constituent assembly is an attempt to sideline a democratically elected National Assembly even further. According to constitutional law, the new constituent body could overrule the executive, legislature and the judiciary.
Mr Maduro has said he wants at least half its members to come from his traditional powerbase - the poor, working classes and other civic associations. He says it will hand back power to the people and bring peace to Venezuela.
It seems to have done precisely the opposite.
Mr Maduro was elected in 2013 to succeed the late Hugo Chavez, a popular figure who introduced wide-ranging social welfare programmes.
But since then, falling prices for Venezuelan oil exports have cut government revenue and there have been shortages of food, baby milk, medicine and other basics.
The International Monetary Fund has forecast that inflation in Venezuela will be above 700% this year.
Presidential elections are due at the end of next year.