The shift in power also was seen as a signal in some capitals that the United States would put a greater emphasis on trade policy and human rights.

Many watching the election said the results were a significant blow to President Bush's presidency.

"Although his term will not end within the next year, I think Bush is already turning into a lame duck," Yuzo Yamamoto, 60, the manager of a Tokyo business consulting firm, said as Democrats won control of the House and challenged Republican dominance in the Senate in midterm elections Tuesday.

Outside observers saw the bloodshed in Iraq as the major driving force behind the Democrats' success.

"Voters have punished the Republicans. They are not happy with the way the leadership has handled the Iraq war," said Chandra Muzaffar, president of the Malaysia-based think-tank International Movement for a Just World.

Bush's foreign critics cheered in Vietnam, and in Muslim-dominated countries such as Indonesia and Malaysia.

"The Republicans lost in the election because the American voters are now fed up and bored with the war," said Vitaya Wisetrat, a prominent, anti-American Muslim cleric in Thailand. "The American people now realise that Bush is the big liar."