He added that Chavista candidates profited from empathy with Chavez and his Bolivarian project. "This ended up being basically a national election. In each of these individual races, it was much more a national election about Chavez than about the local candidates," Smilde said.
Other analysts say that Chavista candidates also won key races because they had more resources to mobilize voters than opposition candidates, who do not count with the support of the national government for things like busing people to voting stations, and get out the vote campaigns.
Francisco Toro directs the Venezuelan politics blog Caracas Chronicles. He said that the opposition lost partly because its supporters were "demoralized" after losing the October presidential elections, and may have not turned out in such large numbers. But Toro also provided the following hypothesis for the opposition's defeat in the crucial Zulia state.
"[Chavista candidate] Arias Cárdenas has been running a virtual parallel governorship there for years," Toro wrote in a Gchat conversation. "It's called CorpoZulia and while it's technically a regional development agency it was far better funded than the actual governorship. So there are clientelist networks already in place there."
Toro noted that in rural states like Trujillo and Cojedes, Chavista candidates won with huge margins of 30 percent and more. He said that these results could've occurred because a large portion of the residents of those states have come to depend on the Venezuelan government for their jobs and their livelihoods.
"People in rural states always tend to be more dependent on public spending than in urban areas, where there are some alternative livelihood strategies. In such [rural] areas it takes a lot to mobilize people to vote against the incumbent," Toro wrote.
The Venezuelan constitution says that if Chavez is unable to start his fourth term in office on January 10th, elections must be held within 30 days. If he starts his term but dies within the first four years of this six-year term, elections must also be held within a month.
According to Toro and Smilde, Sunday's results suggest that a Chavista candidate like Vice President Nicolas Maduro would enter presidential elections as the favorite, specially if they are held soon.
But both analysts said that in the scenario of Chavez passing, there are too many variables to say who would win for sure.