FOR THE FIRST TIME in nearly a half- century, a leader of the Southeast Asian nation of Burma will visit the White House on Monday. President Obama’s invitation is a sign of how quickly things have changed inside President Thein Sein’s nation of 50 million or so people and in bilateral relations. The visit should celebrate the progress — and spur further needed change.

For decades one of the world’s most isolated and repressive nations, Burma in the past two years has opened dramatically. The reform government of Mr. Thein Sein, a former army general, has freed hundreds of political prisoners, relaxed censorship laws, allowed opposition leader Aung San Suu Kyi to contest a seat in parliament (she won with ease) and loosened its grip on the economy . Foreign investors are knocking on the door, newspapers in the major city of Rangoon are circulating freely and political parties are looking toward national elections in 2015.

How free will those elections be? Under Burma’s constitution, the military retains a quarter of parliamentary seats and, essentially, veto power over government actions. Aung San Suu Kyi is barred from the presidency. Prisoners who have been released — including another 20 or so late last week — remain in legal purgatory, on a kind of parole that leaves the government essentially free to lock them up again. Some promises made by the government, including to Mr. Obama when he visited six months ago, have yet to be fulfilled: granting the U.N. High Commissioner for Human Rights permission to open an office, for example, or allowing humanitarian access to areas of ethnic conflict. Meanwhile, reform has been accompanied by terrible violence against Muslim minorities, which, according to human rights groups, has been abetted by state officials.

How to respond to this mixed picture? The administration is generally inclined to focus on the full half of the glass. It has relaxed economic sanctions and agreed to use, in some circumstances, the regime’s preferred word for the country, Myanmar. U.S. officials say the focus of this visit will be how to keep reforms moving forward, possibly with the encouragement of more trade. Burmese expectations are running high, the officials say, and the government has to show results if it is to beat back the hard-liners who want to slow or torpedo reform.

Congress is more skeptical and will apply some braking action to the bilateral opening. Legislators turn the argument around: If there’s no penalty to the government when it stalls reform, then Mr. Thein Sein will have no way to persuade hard-liners that further action is needed. Burma could easily get stuck along the transitional road, winding up with Chinese-style crony capitalism and Russian-style faux elections.

To the extent U.S. policy can influence the outcome, it needs to find a balance that acknowledges the progress, while keeping in mind that Burma — or Myanmar — has a long way to go before it is a true democracy.