But the realities of Mr. Maduro’s Venezuela may be hard to overcome.

Like his predecessor, Hugo Chávez, Mr. Maduro has used the largess of the state — even food, which the government controls — to rally voters and mobilize them on Sunday. Even so, a large majority of voters, particularly in the opposition, is expected to heed the call to abstain. And with the opposition boycotting the vote, few auditors who are not aligned with Mr. Maduro will be reviewing the results.

Beyond that, many voters are simply gone. More than a million Venezuelans have recently fled the country and its collapsing economy, a diaspora that is deeply angered with Mr. Maduro but unlikely to vote on Sunday, analysts say.

“Is the vote fair? It’s clearly not fair,” said David Smilde, a professor of sociology at Tulane University who studies Venezuela. “But sometimes, even in unfair conditions, it’s possible for the opposition to win.”

Mr. Falcón likes to argue that he is best positioned to lead the divided country because he came from the very party he aims to defeat. After Mr. Chávez was elected in 1998, Mr. Falcón helped rewrite the Constitution, then rose to become mayor of Barquisimeto, a large city, and governor of the surrounding state, Lara.

Accounts differ on why Mr. Falcón left the party in 2010. Most analysts say it was because Mr. Chávez was sidelining him as a rising star. Mr. Falcón says he felt that the governing party’s drive to nationalize private assets was leading it to an economic disaster.

Mr. Falcón continued on as governor as a member of the opposition, but lost his seat last year. He wasted little time in mounting a bid for the presidency and working out what he says is a remedy for the country’s failing economy.

His first step would be to switch to the dollar.

Mr. Falcón argues that the country’s most painful economic problems, such as low wages, stem from runaway inflation.