Myanmar's leaders may have the best of reasons to believe that their day in the sun has arrived. US Secretary of State Hillary Rodham Clinton is in the country, the highest-profile American official to visit since the military seized power in 1962. Democracy icon Aung San Suu Kyi will run in a by-election expected next month, giving the parliament much-needed legitimacy. China, the isolated nation's staunchest ally, has pledged stronger ties and Southeast Asian neighbours have promised it the 2014 chair of their regional grouping. President Thein Sein could easily view the developments as rewards. Since taking office in March at the helm of a civilian-led government, albeit one run by former junta generals, he has announced a succession of measures that have given critics cause for optimism. Starting with Suu Kyi's release from house arrest little more than a year ago, the moves have gathered pace and mushroomed, with an amnesty for hundreds of political prisoners, the loosening of media controls and efforts to reach out to ethnic rebels and minorities. There would seem a genuine effort to serve the nation's people. Western nations have for two decades had sanctions against the junta which hopes Clinton's visit signals the easing of those imposed by the US. If its moves are genuine, that should happen. But the efforts so far made are only a start and much more has to be done. There is every reason for caution. Despite the changes, doubts remain that Myanmar is really opening up. More than 1,800 opponents of the regime remain behind bars. The constitution enshrines military rule and while it remains in place, real power lies in the generals. For half a century, the generals have used Myanmar's resources to enrich themselves. Suspicions abound that they are using the pretence of democracy to reap further gains. Clinton should explore options and Suu Kyi and Asian nations work with the government, but far more is needed to show that intentions are genuine.