There have been previous cases of leaders in other countries vanishing from public view for long stretches due to health problems.
Fidel Castro, for one, has appeared in public only occasionally since he fell ill in 2006 and formally stepped aside from the presidency less than two years later.
In Nigeria, President Umaru Yar'Adua left the country for medical treatment in 2009 and died months later.
Venezuelan lawmakers voted last month to indefinitely postpone Chavez’s Jan. 10 inauguration. The opposition argued that was unconstitutional, but the Supreme Court sided with the government and ruled that the president could be sworn in before the court at a later date.
‘‘I don’t think I'm exaggerating in saying that what’s happening in Venezuela is historically unheard of,’’ Valles said in a telephone interview. ‘‘We've never before seen a political process where a term is indefinitely extended.’’