President Obama meets with Burmese opposition leader Aung San Suu Kyi in November 2014. It was their second meeting. (Nyein Chan Naing/European Pressphoto Agency)

On a short flight aboard Air Force One, President Obama placed a phone call he hoped would have long-lasting implications.

On the other end of the line was Aung San Suu Kyi, the leader of Burma’s democratic opposition, whose release from 15 years of house arrest had been the clearest signal that the nation’s military junta was serious about ending a half-century of isolation.

As he flew from Australia to Bali, Indonesia, in the fall of 2011, the president asked for Suu Kyi to give her blessing to his administration’s lending its weight to Burma’s reform process. She said yes.

Obama’s bet on Burma comes due Sunday, as voters in the nation of more than 50 million head to the polls for a national election that observers say could be the most open and democratic in five decades. The results could also go a long way in determining the success of Obama’s efforts to bolster U.S. leadership in Southeast Asia, as well as reflect on the judgment of a possible successor, Hillary Rodham Clinton, who as secretary of state played a key role in the administration’s policy of engagement in Burma.

For Obama, who has made two trips to the country, including last fall, the success or failure of Burma’s reform represents more than just a bet on an impoverished Southeast Asian nation whose location next to China makes it an important strategic partner. It will also go down as a referendum on his philosophy of U.S. leadership abroad.

Burma will hold a landmark election on Nov. 8. Even though Nobel laureate Aung San Suu Kyi’s political party is one of the most popular in the country, she won’t become president. Here’s why. (Jason Aldag and Andrew Katz/The Washington Post)

In his inaugural address in 2009, Obama pledged to “extend a hand” to authoritarian regimes if they were willing to “unclench their fist.” Although he was referring primarily to Iran, Obama’s words rang true for other regimes. Before his detente with Cuba, before his nuclear deal with Tehran, there was Burma.

Climate of churn

Sunday’s election represents an important step in the nation’s halting reform effort. But it is also certain to illustrate how far Burma, also known as Myanmar, still must go to make good on the promise Obama imagined four years ago.

Suu Kyi, 70, the head of the National League for Democracy, has been constitutionally barred from becoming president, having been disqualified because she was married to a Briton and her two sons are British. Voter registration rolls in many parts of the country are said to be rife with errors and omissions. Widespread ethnic violence against the Rohingya Muslim minority probably will keep numerous voting stations shuttered out of fear. And the ruling Union Solidarity and Development Party has mandated that the military will retain at least 25 percent of the seats in parliament, regardless of the election’s outcome.

“There’s a lot of churn, a lot of complexity. No one knows what’s going to happen,” said Ben Rhodes, a deputy national security adviser for Obama who traveled to Burma two weeks ago to meet with government leaders, civil society groups and international election monitors.

“There is campaigning across the country but also a fear there’s going to be intimidation,” Rhodes said. “It’s a climate of uncertainty. . . . What’s important for people to understand is that the story does not end on November 8 after holding elections.”

If international monitors report widespread fraud or intimidation, or if Suu Kyi disavows the electoral results or the military refuses to abide by the outcome, it could plunge the nation into political chaos and sow doubts among key supporters in the United States.

The Obama administration eased economic sanctions several years ago after Burmese President Thein Sein released political prisoners and took other steps toward reform. But congressional leaders have been closely monitoring the progress, and U.S. businesses have been hesitant to invest in the country because of the uncertain political climate.

“This election is a test that the government must pass,” Majority Leader Mitch McConnell (R-Ky.) said in a speech on the Senate floor three weeks ago. “If we end up with an election not accepted by the Burmese people as reflecting their will, it will make further normalization of relations — at least as it concerns the legislative branch of our government — much more difficult.”

The movement toward reform was already underway in Burma when the Obama administration decided cautiously to engage with Naypyidaw, the capital city that the military has carved out of the jungle far from the old capital of Rangoon. The military rulers, concerned about China’s creeping influence and hoping to benefit from economic investment from the West, freed Suu Kyi from house arrest in 2010, along with other political prisoners.

Clinton dispatched a top State Department deputy, Kurt M. Campbell, to Burma to test the regime’s commitment to reform, and he recommended moving forward with engagement. After Obama received Suu Kyi’s blessing during the Air Force One flight, he announced at the East Asia Summit in Bali that Clinton, who stood next to him, would within days become the first U.S. secretary of state in more than 50 years to visit Burma.

On the trip home from Indonesia, Clinton aides presented her with a copy of a biographical film about Suu Kyi called “The Lady.”

“The whole team, including the traveling press corps, watched the movie as we flew east across the Pacific back to Washington,” Clinton wrote in her book “Hard Choices.” A year later, after his reelection in November 2012, Obama visited Burma, meeting Suu Kyi at her lakeside villa and telling an auditorium of students at Yangon University that Burma’s “flickers of progress . . . must become a shining North Star for all this nation’s people.”

“We would not be where we are today were it not for the Obama administration,” said Rep. Joseph Crowley (D-N.Y.), a longtime advocate for human rights and democracy in Burma. “There’s been radical change in Burma. To the extent it is fully completed and they have fulfilled their overall promises — no, they haven’t done that yet.”

Awaiting the hammer

Rhodes said he thinks that international election monitors have been given adequate access and will be able to make judgments about the level of transparency Burma reaches during Sunday’s polling. Yet experts said that the outcome is likely to be murky and that it could be days or weeks before U.S. officials reach a full assessment.

At a dinner during his trip, Rhodes sat next to a woman whose husband had been arrested over a post he had made on Facebook a few days earlier. The woman also had served time in prison for political activities, but even she talked about progress that had been made toward a more democratic society, Rhodes said.

“It’s easy to overstate problems because this is a transition in a country that’s been entirely closed,” Rhodes said. “This is going to be a process. It’s not going to look perfect. But what concerns us is when we see seemingly arbitrary arrests. . . . Even if there’s open political speech and open political debate, there’s still the concern about when the hammer is going to fall.

“It’s a mixed picture,” Rhodes said, “but well, well worth the opening. And there’s enormous promise if they can just continue to move in the right direction, recognizing it’s going to take time.”