Correction: An earlier version of this editorial incorrectly represented PresidentObama’s statement after his meeting with Burmese President Thein Sein. He said, “Over the last two years, we’ve seen a steady process in which political prisoners, including Aung San Suu Kyi, have been released and have been incorporated into the political process.” This editorial has been updated.

NOT MANY DICTATORS or military juntas willingly give up power. Will Burma’s regime prove the exception? That was the ever-present though mostly unspoken question as President Thein Sein toured Washington this week.

The Burmese president’s visit to the White House Monday was the first since Lyndon B. Johnson hosted Burma’s leader in 1966. In the nearly half-century since, the Southeast Asian nation of 50 million or so people has been ground into poverty by the misrule of repressive, reclusive generals. But over the past two years, Mr. Thein Sein, a former general, and the rest of his regime have freed political prisoners, relaxed censorship laws and welcomed foreign investment. They have promised parliamentary elections for 2015 in which, at least in theory, people might be allowed to elect a government of their choice for the first time in the nation’s history.

“Over the last two years, we’ve seen a steady process in which political prisoners, including Aung San Suu Kyi, have been released and have been incorporated into the political process,” President Obama said after Monday’s meeting. “But as President [Thein] Sein is the first to admit, this is a long journey and there is still much work to be done.”

In an interview with The Post Sunday, the Burmese leader sounded less than fully committed to that work. He declined to say whether he would support changes to the constitution to allow Aung San Suu Kyi to run for president. He wavered on previous commitments to allow the U.N. High Commissioner for Human Rights to open an office. He supported the military playing a leading political role and said that, as president, he makes decisions “collectively” with the National Defense and Security Council, where the military chieftains sit. Asked about the Rohingya, a Muslim minority that has been the target of violence and ethnic cleansing by Burma’s Buddhist majority, Mr. Thein Sein denied that they exist. “There is no Rohingya among our races,” he said, speaking through an official translator. “We have Bengalis who were brought to do farming during colonial days. Some of them settled.” He spoke approvingly of a 1982 law that has been used to deny them citizenship.

The question for Washington is how best to encourage further reform. The Obama administration has relied on carrots, including Monday’s White House visit and a trade agreement signed Tuesday. Rep. Joseph Crowley (D-N.Y.), a leader in shaping congressional policy toward Burma, also known as Myanmar, said he worries that “we’re getting away from the policy of action for action” — the idea, articulated in Mr. Obama’s first term, that sanctions would be eased incrementally and only in response to continuing progress on reform. Mr. Crowley said he believes Burma is moving in the right direction, but that major problems remain. “The big risk is that we’re going to lose leverage in terms of reform,” he said. Last week, with Rep. Peter T. King (R-N.Y.), Mr. Crowley reintroduced the Burmese Freedom and Democracy Act, which would maintain some sanctions for another year. A dose of congressional skepticism seems well-founded.