Venezuelans voted yesterday on a proposal that would allow socialist President Hugo Chavez to stay in power for as long as he keeps winning elections after a turbulent decade ruling the OPEC nation.
Mr Chavez, who says he needs another 10 years for his revolution to take root, holds a slim edge in polls, but many Venezuelans remain undecided on changing the constitution to lift restrictions on re-election.
A former soldier who often challenges US influence in the region, Mr Chavez narrowly lost a vote in December 2007 to end term limits and if he loses his second try he would have to leave office in 2013 or find another way to change the rules.
"My political destiny will be decided today," Mr Chavez told reporters after voting in the capital. "This is important for me as a human being and as a soldier in this fight."
Booming fireworks and recordings of military bugles playing from trucks woke up residents in Caracas, where Venezuelans started lining up at the polling stations before dawn. Voting went ahead with few problems, authorities said.
Spearheaded by a student movement, the fragmented opposition's campaign slogan is "No is No," referring to the failed 2007 bid to extend the rule of a man they say wants to forge a communist dictatorship centred on his personal rule.
"People want peace, they don't want any more confrontation," Caracas mayor and opposition leader, Antonio Ledezma, said after casting his ballot in the capital.
Confident of victory this time, Mr Chavez, 54, says a win would reinforce his mandate to forge a socialist state and challenge Washington in Latin America. After his last ballot box win in 2006 he sped up aggressive nationalizations.
But with oil prices more than $100 a barrel lower than their peak seven months ago, Mr Chavez has far less income to spend on his programs of clinics, schools and food hand-outs for the poor Venezuelans who have consistently backed him.
Venezuela's currency and sovereign debt have lost value in recent months as investors worry his Cuban-inspired socialist revolution will burn through international reserves.
The Venezuelan leader, who calls former Cuban leader Fidel Castro his mentor, has carved out a place for himself as the standard bearer for anti-US sentiment in the region, wielding his nation's oil to counter US free-market proposals.
Leftist allies in Ecuador and Bolivia have joined Mr Chavez in rewriting constitutions to extend their own rule and increase state control over economies in the name of bringing wealth to the neglected poor majority.
Mr Chavez warned poor supporters they could lose social programmes if he is unable to run again for re-election. He has also adopted a familiar tactic of accusing the opposition of joining a coup plot directed from the United States and planning to cry fraud if he wins.
Opposition leaders hope to capitalize on discontent over high crime rates and soaring living costs. But Mr Chavez, whom supporters adoringly call "El Comandante," has shown resilience.
He survived a putsch and national strikes and has won all but one election since first coming to office in 1999.
Late yesterday both sides claimed exit polls showed they were winning.