Polls have opened in Venezuela, where people are voting Sunday in a presidential election whose outcome will either lead to a seismic shift in politics or extend by six more years the policies that caused the world’s worst peacetime economic collapse.

Whether it is President Maduro who is chosen, or his main opponent, retired diplomat Edmundo González, the election will have ripple effects throughout the Americas. Government opponents and supporters alike have signaled their interest in joining the exodus of 7.7 million Venezuelans who have already left their homes for opportunities abroad should Mr. Maduro win another term.

Polls opened at 6 a.m. local time. The number of eligible voters is estimated to be around 17 million.

Authorities set Sunday’s election to coincide with what would have been the 70th birthday of former President Hugo Chávez, the revered leftist firebrand who died of cancer in 2013, leaving his Bolivarian revolution in the hands of Mr. Maduro. But Mr. Maduro and his United Socialist Party of Venezuela are more unpopular than ever among many voters who blame his policies for crushing wages, spurring hunger, crippling the oil industry and separating families due to migration.

Mr. Maduro, 61, is facing off against an opposition that has managed to line up behind a single candidate after years of intraparty divisions and election boycotts that torpedoed their ambitions to topple the ruling party.

Mr. González is representing a coalition of opposition parties after being selected in April as a last-minute stand-in for opposition powerhouse Maria Corina Machado, who was blocked by the Maduro-controlled Supreme Tribunal of Justice from running for any office for 15 years.

Ms. Machado, a former lawmaker, swept the opposition’s October primary with over 90 percent of the vote. After she was blocked from joining the presidential race, she chose a college professor as her substitute on the ballot, but the National Electoral Council also barred her from registering. That’s when Mr. González, a political newcomer, was chosen.

Sunday’s ballot also features eight other candidates challenging Mr. Maduro, but only Mr. González threatens Mr. Maduro’s rule.

Venezuela sits atop the world’s largest proven oil reserves, and once boasted Latin America’s most advanced economy. But it entered into a free fall after Mr. Maduro took the helm. Plummeting oil prices, widespread shortages and hyperinflation that soared past 130,000 percent led first to social unrest and then mass emigration.

Sanctions from President Trump’s administration seeking to force Mr. Maduro from power after his 2018 reelection — which the United States and dozens of other countries condemned as illegitimate — only deepened the crisis.

In recent days, Mr. Maduro has crisscrossed Venezuela, inaugurating hospital wards and highways and visiting rural areas where he had not set foot in years. His pitch to voters is one of economic security, which he underscores with stories of entrepreneurship and references to a stable currency exchange and lower inflation rates.

The capital, Caracas, saw an increase in commercial activity after the pandemic, bolstering an economy the International Monetary Fund forecasts will grow 4 percent this year — one of the fastest in Latin America — after having shrunk 71 percent from 2012 to 2020.

But most Venezuelans have not seen any improvement in their quality of life. Many earn under $200 a month, which means families struggle to afford essential items. Some work second and third jobs. A basket of basic staples — sufficient to feed a family of four for a month — costs an estimated $385.

The opposition has tried to seize on the huge inequities arising from the crisis, during which Venezuelans abandoned their country’s currency, the bolivar, for the American dollar.

Mr. González and Mr. Machado focused much of their campaigning on Venezuela’s vast hinterland, where the economic activity seen in Caracas in recent years didn’t materialize. They promised a government that would create sufficient jobs to attract Venezuelans living abroad to return home and reunite with their families.

An April poll by Caracas-based Delphos said about a quarter of Venezuelans were thinking about emigrating if Mr. Maduro wins Sunday. Most Venezuelans who migrated over the past 11 years settled in Latin America and the Caribbean. In recent years, many began setting their sights on the United States.

Both campaigns have distinguished themselves not only for the political movements they represent but also on how they have addressed voters’ hopes and fears.

Mr. Maduro’s campaign rallies featured lively electronic merengue dancing as well as speeches attacking his opponents. But after he caught heat from leftist allies such as Brazil’s President Lula da Silva for a comment about a “bloodbath” should he lose, Mr. Maduro recoiled. His son told the Spanish newspaper El Pais that the ruling party would peacefully hand over the presidency if it loses — a rare admission of vulnerability out of step with Mr. Maduro campaign’s triumphalist tone.

In contrast, the rallies of Mr. González and Ms. Machado prompted people to cry and chant ” Freedom! Freedom! ” as the duo passed by. People handed the devout Catholics rosaries, walked along highways and went through military checkpoints to reach their events. Others video-called their relatives who have migrated to let them catch a glimpse of the candidates.

During a rally in mid-May, Mr. González, 74, asked supporters to imagine “a country in which our airports and borders would be filled with our children returning home.”