President Barack Obama is preparing to visit Asia, with a stop in Burma. His trip is meant to encourage the country, also known as Myanmar, to continue on the reform path. But he should win a commitment to further reform before his arrival.

Until recently Burma competed with North Korea for the title of worst-governed nation on Earth. Long-running ethnic conflicts in the east killed thousands and displaced millions. After winning a free election Nobel Laureate Aung San Suu Kyi spent most of the last two decades under house arrest, while thousands of other democracy activists languished in prison. The government’s botched response to the 2008 typhoon left hundreds of thousands suffering.

Two years ago, the junta held a fixed election. It looked like nothing much had changed. But then the top generals retired and chose U Thein Sein, a former colleague, as president.

Suu Kyi has been freed, political prisoners have been released, by-elections have been held, press censorship has been eased, blacklists on foreign visitors have been ended, and ceasefires have been reached with several ethnic groups. The military-dominated legislature even has been demonstrating growing independence from the regime.

The Burmese people are hopeful but wary. A decade ago the junta liberalized, only to quickly reverse course. Democratization has proceeded far further this time, but journalist Aung Zaw argued that the changes are “still fragile.” Earlier this year, Human Rights Watch pointed to “abundant evidence of continuing systematic repression.” Several hundred political prisoners remain in custody.

Ethnic violence directed against the Muslim Rohingyas has ravaged Rakhine State in the northwest. Bitter fighting continues between the military and Kachin forces in the northeast.

Most important, observed Tom Malinowski of Human Rights Watch: “It’s not at all clear whether the military is going to cede the strong power it still has over most aspects of life in Burma.” Is the military prepared to relinquish all of its privileges, especially in the face of demands for justice over past abuses? The next scheduled general election remains three years distant, after which the 67-year-old Thein Sein has indicated that he might retire.

The power lines in Naypyidaw (the capital, moved from Rangoon in 2006) remain obscure. Suu Kyi urged continuing caution in assessing Burma’s progress, warning against “reckless optimism.” Her cousin Sein Win, who headed the recently dissolved government-in-exile, noted: “There are many changes, but there need to be many more changes, and that is not happening now.”

Still, the government continues to reform. Before Aung San Suu Kyi visited the U.S. in September, the regime freed 514 prisoners, about 80 of them political. At the same time, Naypyidaw replaced a repressive junta-era press agency.

The government has also announced plans to inaugurate an independent monetary policy. Moreover, the Thein Sein administration is pushing a new investment code. Energy investment is exploding this year, as the authorities auction off oil- and gas-exploration permits.

Meanwhile, Naypyidaw has begun to distance itself from China, its neighbor and long-time benefactor. A desire to achieve some geopolitical balance — Thein Sein visited China before going to the U.S. in September — may have encouraged the military regime to reach out to the West.

Past reforms should be rewarded and future changes should be encouraged. That means lifting economic sanctions in order to encourage further democratization.

For instance, Burmese imports are still banned. Derek Mitchell, America’s ambassador to Burma, expressed Washington’s commitment to work with the new government in easing U.S. rules “even if fully extracting ourselves from the Byzantine array of restrictions imposed over the years may take some time.” In fact, while visiting America Suu Kyi called for lifting all restrictions now: “There are very many other ways in which the United States can help us to achieve our democratic ends.”

President Obama’s trip is another reward. Malinowski worries that the presidential visit is premature: “It would not be a good thing if the president leaves Burma and there are still political prisoners there.” In contrast, Gordon Hein of the Asia Foundation approved: “If one waited until every major issue was successfully resolved that would be a long wait for any country.” Since such a visit will be seen as validating the regime, Washington should insist on a promise of additional reforms — perhaps the release of all political prisoners — as a quid pro quo.

The transformation of Burma remains a long, difficult process. However, much has changed. “We are not yet at the end of our struggle,” Suu Kyi observed, “but we are getting there.”

Two years ago few people, in or out of Burma, predicted genuine reform. Today almost everyone expects it. The ultimate objective must be to let the Burmese people take charge of their own destiny.