WASHINGTON  President Obama reversed the most disputed counterterrorism policies of the Bush administration on Thursday, declaring that “our ideals give us the strength and moral high ground” in the fight against Al Qaeda. But Mr. Obama postponed for months decisions on complex questions the United States has been grappling with since the terrorist attacks of 2001.

Mr. Obama signed executive orders closing the detention camp at Guantánamo Bay, Cuba, within a year; ending the Central Intelligence Agency’s secret prisons; and requiring all interrogations to follow the noncoercive methods of the Army Field Manual.

“We intend to win this fight,” he said. “We are going to win it on our own terms.”

His actions on the second full day of his presidency won praise from human rights groups and Democrats in Congress, who said the new policies would help restore the United States’ moral authority. Mr. Obama invited to the signing ceremony 16 retired generals and admirals who had spoken out against what they called torture. Their passionate appeal to end harsh interrogations “made an extraordinary impression on me,” he said.

Mr. Obama’s orders struck a powerful new tone and represented an important first step toward rewriting American rules for dealing with terrorism suspects. But only his decision to halt for now the military trials under way at Guantánamo Bay seemed likely to have immediate practical significance, with other critical policy choices to be resolved by task forces set up within the administration.