A look at efforts to extend term limits worldwide

The West African nation of Niger holds a referendum Tuesday that will end presidential term limits if passed. Referendums on term limits have been held worldwide in recent years. While they have failed in a handful of cases — including Honduras, Malawi, Nigeria and Zambia — most attempts have succeeded. Here is a look at some nations where there have been efforts to extend term limits:

_ALGERIA: Algeria's parliament overwhelmingly approved a constitutional amendment in 2008, allowing President Abdelaziz Bouteflika to win a third term in April.

_BOLIVIA: Voters approved a new constitution in January that gives President Evo Morales a shot at remaining in office through 2014 if he wins elections scheduled for December.

_CAMEROON: The National Assembly voted in 2008 to change the constitution to remove term limits despite a two-term limit in the 1996 constitution. The move enabled President Paul Biya, who has ruled since 1982, to stay in office.

_CHAD: In June 2005, a successful referendum was held to eliminate a two-term constitutional limit, enabling President Idriss Deby to swear in for a third term in 2006.

_ECUADOR: A new constitution approved by Ecuador's voters in September made President Rafael Correa eligible to run again in 2013 for another four-year term. It also gave the president greater control over spending and the central bank. Correa was re-elected in April.

_GABON: The late Omar Bongo ascended to the presidency in 1967 and held power until his death this year. In 2003, Bongo changed the constitution to get rid of term limits so he could continue running for life. Several of his children have now announced their intent to run for his job.

_HONDURAS: Before his ouster in a June 28 coup, President Manuel Zelaya had been trying to organize a referendum to gauge popular support for a constitutional overhaul, defying court orders declaring the vote illegal. Opponents say he was trying to extend his presidential term and used this as the rationale for the coup. Zelaya denies such intentions and is in exile in neighboring Nicaragua.

_TUNISIA: In 2002, Tunisians overwhelmingly approved a referendum that removed the three-term limit on the presidency. The move allowed President Zine Abidine Ben Ali, in office 1987, to seek another term in office. He will run for a fifth term in October.

_UGANDA: President Yoweri Museveni's supporters abolished presidential term limits before the 2006 elections, which he won. Museveni led an insurgency to take power in 1986.

_VENEZUELA: President Hugo Chavez won a referendum in February abolishing term limits and allowing him to run for re-election indefinitely. Chavez has been in office since 1999. The next presidential election is to be held in 2012.