On 2 December, Venezuelans will decide whether or not to approve a package of constitutional reforms, which include ending the limits on presidential terms.
Anti-Chavez students say the reforms would restrict freedoms
The changes, which would affect about a quarter of the constitution's articles, were approved by the National Assembly, which is controlled by President Hugo Chavez's supporters.
The referendum is the last step needed for the changes to come into force. Around 60% of voters are expected to take part.
Doesn't Venezuela already have a new constitution?
Yes. President Chavez, who came to power in 1998, introduced a new "Bolivarian" constitution in 1999. He said the old one represented "the interests of the oligarchic sector".
But he now says more changes are needed to complete the transition to a "socialist republic".
The 1999 constitution increased the presidential term of office from five to six years and allowed a president to be re-elected once.
Under the previous constitution, the president could not be re-elected.
The 1999 constitution also introduced provisions for national presidential recall referendums, which means that Venezuelan voters have the right to remove their president from office before the expiration of the presidential term.
What are the main changes proposed?
Mr Chavez initially proposed amending 33 articles of the constitution, but the National Assembly added another 36 changes.
Among some of the main changes are:
Allowing the indefinite re-election of the president - not applicable to any other political post
Increasing the presidential term from six to seven years
Introducing changes to the country's administrative structure
Ending the autonomy of the central bank
Placing the president in charge of administering the country's international reserves
Reducing the maximum working week from 44 to 36 hours
Is President Chavez expected to win?
Mr Chavez has invested millions of dollars into social projects
It is not clear. Unlike previous referendums and elections, when Mr Chavez always looked guaranteed to win, some polls have suggested he might actually lose.
This in itself is surprising, although it is difficult to say how reliable or objective these surveys are.
Does this mean that the opposition has become stronger?
The Venezuelan opposition won the support of 37% of voters at the last presidential election, but it has little power.
The National Assembly is fully controlled by Chavez supporters and the judicial system is heavily influenced by the president as well. The only mechanism the opposition has to voice its positions is the media.
Earlier this year, the most popular television station, RCTV, which in 2002 broadcast calls to overthrow Mr Chavez's administration, did not have its licence renewed.
Why then could Mr Chavez lose this time around?
The marches against the referendum have been led mainly by groups of opposition students, not the traditional opposition parties.
Also, some Chavez supporters are not convinced about the changes he wants to introduce, especially the indefinite re-election of the president.
Some mayors and governors are also unhappy with the administrative regions he wants to create.
Some analysts believe Mr Chavez is alienating his supporters.
General Raul Baduel, a former close supporter who served as defence minister, has likened the constitutional reform to a military coup.
President Chavez, sensing problems within his ranks, has repeatedly asked his allies to decide whether they are for or against him.
What happens if Mr Chavez loses?
His present presidential mandate expires in January 2013. However, this does not mean that if he loses he will be a lame-duck for the next five years.
The National Assembly has granted Mr Chavez an "enabling law" (ley habilitante), which allows him, over the period of one year, to pass laws on specified issues as decrees. The National Assembly could easily keep renewing this law.
But his defeat would nonetheless be a huge boost to the opposition, especially to the student groups which have been leading the marches.
These groups may become the main opposition voice given the disarray of the traditional parties and push for another recall referendum half-way through Mr Chavez's present mandate (in 2010) just like the opposition did in 2004.
President Chavez has said that if he loses it will be time to start looking for a successor. It is difficult to say if he was being serious, but one thing looks certain - Mr Chavez will not go without a fight.
Why does President Chavez have such a strong political base?
From 1958 until 1998, Venezuela was dominated by two major parties, the centre-right Christian Democratic Party (Copei) and the centre-left Democratic Action (AD).
After his victory in the 1998 election, Mr Chavez, who had previously tried to take control of the country in a failed military coup in 1992, set out to destroy this two-party system, which he described as oligarchic.
President Chavez has been working to set up a socialist republic by reforming the political and social systems.
He has nationalised key industries, such as telecommunications and electricity. He has also increased government control of the oil and gas sectors.
He has invested millions of dollars from Venezuela's oil revenues into social projects.
Since 2003, he has maintained a strict price regime on some basic foods like coffee, beans, sugar and powdered milk. This measure was designed to curb inflation, but it has also led to shortages of staple foods.
Today Venezuelan politics is divided between a pro- and an anti-Chavez camp. His supporters say he has given a political voice to millions of poor Venezuelans who were disregarded by the "traditional" political parties.
His opponents describe him as a populist who is looking to entrench himself in power.