Venezuela Holds a Key Vote on Sunday. Here’s What You Need to Know.

One million Venezuelans headed to the polls on Sunday to elect an opposition candidate to face President Nicolás Maduro in presidential elections in 2024, a contest that could prove pivotal to the fate of a country that has endured a decade of economic crisis and authoritarian governance.

Mr. Maduro came to power in 2013, after the death of Hugo Chávez, the founder of the country’s socialist-inspired revolution. Under Mr. Maduro, Venezuela, once among the richest countries in Latin America, has undergone an extraordinary economic collapse, leading to a humanitarian crisis that has sent more than seven million people fleeing.

But the Maduro government and the opposition signed an agreement on Tuesday meant to move toward free and fair elections, including allowing the opposition to choose a candidate for next year’s presidential contest.

Sunday’s election, however, will take place with no official government support. Instead, the vote is being organized by civil society, with polling stations in homes, parks and the offices of opposition parties.

The leading candidate is María Corina Machado, a center-right former legislator, who has declared herself the country’s best shot yet at ousting the socialist-inspired government that has governed since 1999.

Here is what you need to know about Sunday’s election:

How are relations between Venezuela and the United States?

The United States for years has leveled sanctions on some Venezuelan leaders, but the Trump administration significantly tightened them in 2019, after an election that was widely viewed as fraudulent, in which Mr. Maduro claimed victory.

Mr. Maduro has long sought the lifting of the sanctions, which have strangled the economy, while the United States and its allies in the Venezuelan opposition have wanted Mr. Maduro to allow competitive elections that could give his political opponents a legitimate chance at winning.

The past week has seen the most significant softening of relations between Venezuela and the United States in years.

Venezuela’s authoritarian government has agreed to accept Venezuelan migrants deported from the United States, signed an agreement with opposition leaders devised to move toward a free and fair presidential election, and released five political prisoners.

In exchange, the United States has agreed to lift some economic sanctions on Venezuela’s oil industry, a vital source of income for the Maduro government.

What effect does the easing of sanctions have?

The sanctions relief announced this past week allows Venezuela’s state-owned oil company to export oil and gas to the United States for six months. For the past few years, the Venezuelan government has been exporting oil to China and other countries at a significant discount.

While the move is expected to be a significant boon to Venezuela’s public finances, analysts said that poor infrastructure and a reluctance by some outside investors to quickly enter the Venezuelan market present significant challenges.

What is driving these developments?

Among the factors driving this flurry of new policies is Venezuela’s increased geopolitical importance.

The South American country is home to the largest proved oil reserves in the world, and there is growing U.S. interest in those reserves amid concern over a broader conflict in the Middle East and the war in Ukraine, which has threatened access to global oil supplies.

While it would take years for Venezuela’s hobbled oil industry infrastructure to recover, the country’s petroleum reserves could be crucial in the future.

The Biden administration is also increasingly interested in improving the economic situation in Venezuela to try to stem the surges of Venezuelan migrants seeking to reach the United States.

Could this election really lead to a change in Venezuela’s leadership?

Experts are skeptical that Mr. Maduro will willingly give up power, or allow elections to take place if there is a chance he might not win.

His government is being investigated by the International Criminal Court for possible crimes against humanity, and the United States has set a $15 million reward for his arrest to face drug trafficking charges. Leaving office could mean lengthy jail terms for Mr. Maduro and his associates.

So despite the significance of the recent announcements, some analysts worry that Mr. Maduro is playing both the opposition and the U.S. government, and could ultimately end up with everything he seeks: relief from the sanctions; at least some international recognition for his bow toward fair elections; and a victory next year that allows him to retain power.

The United States has tried to prevent that from happening by making clear that the sanctions could be reinstated at any time.

But some analysts say that could be difficult if companies take advantage of the sanctions relief and start investing in Venezuela. If that happens, it might be hard to put the sanctions back in place.

Who is María Corina Machado, the leading candidate?

Ms. Machado is a veteran politician nicknamed “the iron lady” because of her adversarial relationship with the governments of Mr. Maduro and Mr. Chávez. She is viewed by some supporters as courageous for staying in the country when many other politicians have fled political persecution.

Her proposals to open up the free market and reduce the role of the state have earned her a loyal base across social classes.

But as she has promoted her candidacy, Ms. Machado’s campaign has been plagued by violence and government surveillance.

She has been beaten by people holding Maduro signs, and had animal blood thrown at her at one rally at which The New York Times was present. She has been followed by military intelligence police, and she bypasses police roadblocks by riding on the motorcycles of her supporters.

Could Ms. Machado actually win the presidency?

Polls suggest that Ms. Machado is likely to win the primary, which has 10 candidates.

The group of contenders, who represent a spectrum of ideological views, includes former governors, activists, professors and lawyers, though none seems to have broken through enough to pose a serious challenge to Ms. Machado.

But the biggest question is whether Ms. Machado, assuming she wins, will be able to participate in the general election.

Mr. Maduro’s government has banned Ms. Machado from running for office for 15 years, claiming that she did not complete her declaration of assets and income when she was a legislator. These types of disqualifications are a common tactic used by Mr. Maduro to keep strong competitors off ballots.

Despite an agreement this week to move toward competitive election conditions, the Maduro government has shown little indication that it will allow Ms. Machado to run.

The Biden administration has made clear that it expects Mr. Maduro to reinstate banned candidates or face the restoration of sanctions.

If Ms. Machado is not allowed to run in 2024, the opposition could put forward another candidate. But it is unclear whether Ms. Machado would willingly step aside, and if the opposition would rally around a single new candidate or split the vote, essentially handing Mr. Maduro the election.