WASHINGTON » Standing in the grand presidential palace in Senegal this week, President Barack Obama detoured from his diplomatic mission to Africa to offer a message to his own constituents back home.

"The American people don’t have a Big Brother who is snooping into their business," he said, amplifying his answer to a question about the hunt for a national security leaker. "I’m confident of that. But I want to make sure everybody is confident of that."

Wherever he goes, whatever else is on his agenda, Obama in recent weeks has made a point of reassuring Americans that he is not spying on them. His statements are part of a carefully orchestrated White House damage-control effort in response to revelations about surveillance programs that have unnerved many Americans and exposed him to criticism from the political left and right.

The strategy reflects the sensitivity of a president elected after assailing counterterrorism policies that he ultimately adopted in some form after taking office. With a blitz of statements, briefings, interviews, Twitter messages and selected disclosures, the White House has pushed back aggressively, arguing that his policies are both necessary to protect the nation against terrorists and yet more respectful of civil liberties and checks and balances than those initially enacted by President George W. Bush.

Obama’s aides said they were responding to disclosures about secret National Security Agency programs by trying to be more transparent about them, even as the administration chases the man who disclosed them across the world to prosecute him for espionage. They also say the president really wants a debate.

"We could have just retrenched," said Benjamin J. Rhodes, a deputy national security adviser to the president. "Instead, we worked with the interagency process to make more information available and open a window into the president’s thinking. We’re trying to channel the interest in this issue into greater transparency and a very deliberate review of how we go about doing business."

But critics of the programs say the White House is being disingenuous and making dubious claims about their effectiveness, while supporters of the programs say the White House is giving away too much information and pandering to opponents.

The White House was caught off guard when a government contractor named Edward J. Snowden leaked classified documents on NSA programs to the Guardian and The Washington Post. The documents showed that the NSA was obtaining data about the cellphone calls of millions of Americans, although not their content, and the email and other digital information of foreigners living overseas.

Obama had just given a major speech on terrorism, the most extensive of his presidency, but it focused on drone warfare, the prison at Guantanamo Bay, Cuba, and other issues. Surveillance practices had not been the subject of major public dispute during Obama’s presidency.

"There’s so much attention on the drone issue in particular and to the detention issue, this has just not been at the forefront," said Rhodes. "It’s something the president wanted to get to; privacy concerns have certainly been on his mind."

"But," he added, "it had kind of taken a back seat in the public debate to drones and ultimately that’s what was driving public discussion."

After the newspaper reports about the NSA programs, the White House at first left the public response to James Clapper, the director of national intelligence, who denounced the leaks while justifying the programs. But as the public furor grew, Obama personally took it on.

Traveling in California, the president had aides let reporters know that he would welcome a question about the NSA programs after a health care event, and he used the opportunity to give a lengthy explanation of them. Then the White House invited Charlie Rose to the White House on a Sunday, hoping the conversational nature of his interviews would be an effective way to discuss the surveillance issue.

The White House sent officials to Capitol Hill to placate lawmakers and they so far have conducted 18 briefings. Clapper was sent to talk with NBC’s Andrea Mitchell, while Gen. Keith B. Alexander, the NSA director, was booked onto ABC’s "This Week." The government asserted that 50 plots had been thwarted by the programs and disclosed information about several of them as examples; by this week, Alexander had increased the total to 54 during a speech at a cybersecurity conference.

Obama directed Clapper to consider declassifying more information and last week met with a civil liberties oversight board that has just been fully constituted more than four years after his inauguration.

David Medine, a longtime Federal Trade Commission lawyer who worked on privacy issues and now serves as chairman of the Privacy and Civil Liberties Oversight Board, said the panel’s first task will be to examine the newly disclosed NSA programs and he plans to hold a public workshop, probably on July 9, with academics, experts and advocates.

"We pretty much can say what we think should be done and that’s important," Medine said in an interview. "We don’t report to anybody. We are independent and we can really be free in some ways to really represent the American people’s concerns."

Critics scoff at Obama’s professed desire for a debate.

"When he says he wants to have a debate on this issue, he passed on every opportunity to have a debate about it," said Jennifer Hoelzer, a former aide to Sen. Ron Wyden, D-Ore., who has been a top critic of the secret programs. "You had to wait until someone illegally disclosed it? That seems disingenuous."

Jameel Jaffer, a top official at the American Civil Liberties Union, said a genuine debate was difficult as long as so much information still remains secret.

"The president said he welcomes a debate and we welcome one too, but it’s very hard to have one when so much information is classified," he said. "Information that’s been released through unofficial channels in recent weeks makes clear that what was being withheld should never have been classified in the first place."

On the other side of the spectrum, Marc A. Thiessen, a former aide to Bush and defender of his counterterrorism policies who wrote a book subtitled "How Barack Obama is Inviting the Next Attack," has spent the last couple weeks defending Obama for authorizing the secret programs.

But Thiessen said the president and his team have looked "weak and vacillating and defensive" while overreacting by giving out too much information.

"It’s not just that they’re not effectively defending themselves," he said. "It’s that they’re doing more damage by the way they’re defending themselves. They’re pandering to the civil libertarian left and they’re afraid of the libertarian right. So their damage control has done almost as much damage as the leak itself."

Thiessen, who now writes a column for The Post, has some understanding of the situation the White House finds itself in. When Bush’s counterterrorism policies were revealed by the news media, Thiessen wrote a speech for the president defending them while announcing that he would empty secret CIA prisons. Still, he said Obama’s situation is more precarious than Bush’s was. "He’s got a different political dynamic," Thiessen said. "The president has his own base up in arms while we had our base more reflexively behind us. And the opposition is more vocal now."