Currently, there are 12,012,118 people registered to vote in Venezuela, thus the opposition will require 2,402,423 valid signatures in order to have the CNE approve the recall referendum for the President. Opposition figures have suggested numbers between 4 and 5 million voters which may be somewhat unrealistic given the limited time, the threats against public workers and those in the military as well as abstention. This is my attempt at being quantitative on a guesstimate:
While Venezuelans always indicate in the polls that they will vote, when voting time comes around many simply fail to show up. In the last two Presidential elections in 1998 and 2000, despite the enthusiasm for Chávez candidacy, abstention levels reached 33.52% and 43.69% respectively. Thus, when Hugo Chávez received 62.46% of the votes in 1998 and 59.76% in 2000, only 39.21% and 32.05% respectively of eligible Venezuelan voters actually cast a ballot for him. Thus, while the opposition argues that 70% of the electorate badly wants Chávez out of power and abstention levels should be lower, one may argue that the pro-Chávez voters in 1998 and 2000 were equally compelled to go and vote, but abstention levels were nevertheless quite high anyway. (In polls, of those that claim to regularly vote, 76% think that Chavez should be recalled, while of those that regularly do not vote, only 35% think he should be. If true, the final numbers will be much higher than my estimates below)
As a first possible scenario we may consider the 2000 Presidential election, which had an abstention level of 43.69%. This implies that the pool of interested voters would be roughly 6.76 million voters. If we take the range of numbers from current polls that go from 65-74% in favour of the opposition this would yield a total of between 4.39 and 5.00 million signatures. This would an outstanding result for the opposition, since it would indicate an easy recall in a referendum, since both numbers are higher than the 3.757 million votes that Chávez received in the 2000 Presidential election. (Curiously in 1998, with 40% fewer registered voters at the time, Carlos Andres Perez received 3.85 million votes in winning the Presidency in 1988, higher in absolute value than what Hugo Chavez received in either 1998 or 2000)
A true worst case scenario for the opposition can be calculated by assuming that only those that voted in that election against Chávez will be motivated to go out and sign the petition. This is 2.53 million signatures, a number above that required to ask for the recall, but too close for comfort given the fact that signatures may be challenged in Court if the number is too close to the 2.4 million minimum required.
What is difficult to measure is the impact of the threats by the Government against public workers who sign the petition. Some will feel threatened, others will not care. It is not easy to fire public workers in Venezuela, but if Chávez does survive the recall it is not farfetched to imagine a witch hunt against those that sign the recall petition. If we assume public workers are roughly 1.7 million including the centralized and decentralized governments, then roughly three hundred and fifty thousand work for non-Chavista regional governments and are not subject to pressure. Of the remainder, abstention should be the average abstention level of the country leaving only 1.35 million. If the pressure works, we expect only the non-hardcore anti-Chávez to fail to sign the petition. This group is estimated to be in polls 25% of the population leaving roughly 1 million voters who will not vote if the pressure works. This means that the opposition should receive between 3.4 and 4 million voters in the most realistic and probable case. If my estimate is correct, this would represent a huge victory for the opposition, given that it is comparable to the number of people who voted for Chvaez and in the actual recall referendum the vote will be secret.