BANGKOK, Thailand -- U.S. President George W. Bush was to deliver a thumping broadside against Myanmar on Thursday and meet with Burmese dissidents who have heaped praise on his tough policy toward its military rulers.

First lady Laura Bush was to add ammunition with a trip to see Myanmar refugees at the Thai border.

But these salvos during the U.S. president's 24-hour visit to Thailand on Thursday were unlikely to alter the hard-line course charted by Myanmar's generals, who have time and again failed to respond to international pressure for democratic change.

Analysts suggested that Bush might do better by taking up the issue with leaders in China, Myanmar's closest ally with at least some leverage over its leadership. From Thailand, Bush travels on to Beijing, where he will attend the Olympic Games.

Bush, making what is expected to be his last trip to Asia as president, is also to deliver a sweeping address on Asia policy. The White House released the text of the speech nearly 18 hours in advance, as Bush flew to Thailand from South Korea.

Standing out were comments on China's human rights record.

"America stands in firm opposition to China's detention of political dissidents, human rights advocates and religious activists," Bush is to say in the marquee speech of his Asia trip. "We speak out for a free press, freedom of assembly and labor rights -- not to antagonize China's leaders, but because trusting its people with greater freedom is the only way for China to develop its full potential."