Defense Secretary: Libya Did Not Pose Threat to U.S., Was Not 'Vital National Interest' to Intervene White House says nobody knows when U.S military operation in Libya will end.

WASHINGTON, March 27, 2011 -- Secretary of Defense Robert Gates said that Libya did not pose a threat to the United States before the U.S. began its military campaign against the North African country.

On "This Week," ABC News' Senior White House Correspondent Jake Tapper asked Gates, "Do you think Libya posed an actual or imminent threat to the United States?"

"No, no," Gates said in a joint appearance with Secretary of State Hillary Clinton, their first since the Libya operation began. "It was not -- it was not a vital national interest to the United States, but it was an interest and it was an interest for all of the reasons Secretary Clinton talked about. The engagement of the Arabs, the engagement of the Europeans, the general humanitarian question that was at stake."

Gates explained that there was more at stake. "There was another piece of this though, that certainly was a consideration. You've had revolutions on both the East and the West of Libya," he said, emphasizing the potential wave of refugees from Libya could have destabilized Tunisia and Egypt.

"So you had a potentially significantly destabilizing event taking place in Libya that put at risk potentially the revolutions in both Tunisia and Egypt," the Secretary said. "And that was another consideration I think we took into account."

During his campaign for the presidency, in December, 2007, Barack Obama told The Boston Globe that "The president does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation."

Earlier in 2007, then-Senator Hillary Clinton said in a speech on the Senate floor that, "If the administration believes that any -- any -- use of force against Iran is necessary, the President must come to Congress to seek that authority."

Tapper asked Clinton, "Why not go to Congress?"

"Well, we would welcome congressional support," the Secretary said, "but I don't think that this kind of internationally authorized intervention where we are one of a number of countries participating to enforce a humanitarian mission is the kind of unilateral action that either I or President Obama was speaking of several years ago."

"I think that this had a limited timeframe, a very clearly defined mission which we are in the process of fulfilling," Clinton said.

Earlier in the interview, which was taped on Saturday afternoon, Gates extrapolated the White House's timeline on Libya.

"Some NATO officials say this could be three months, but people in the Pentagon think it could be far longer than that. Do you think we'll be gone by the end of the year? Will the mission be over by the end of the year?" Tapper asked

"I don't think anybody knows the answer to that," Gates said.

The United States has been at war in Afghanistan for almost ten years, at war in Iraq for almost eight years and at war in Libya for nine days.

"For all practical purposes, the implementation of a no-fly zone is complete," Gates said. "Now it will need to be sustained, but it can be sustained with a lot less effort than what it took to set it up."

On the humanitarian side, the defense secretary said significant progress has been made.

"We have prevented the large scale slaughter that was beginning to take place, has taken place in some places. And so I think that we are at a point where the establishment of the no-fly zone and the protection of cities from the kind of wholesale military assault that we have seen certainly in the East has been accomplished and now we can move to sustainment," he said.

Regime Change?

President Obama has called for Libyan leader Muammar Gadhafi's departure, but regime change is not one of the goals of the United Nations-led military operations. Tapper asked about this seeming inconsistency.

"So why not have, as part of the mission, regime change, removing Gadhafi from power?" Tapper asked the Secretary of Defense.

"Well, first of all, I think you don't want ever to set a set of goals or a mission -- military mission where you can't be confident of accomplishing your objectives," he said. "And as we've seen in the past, regime change is a very complicated business. It sometimes takes a long time. Sometimes it can happen very fast, but it was never part of the military mission."

Clinton Cites Rwanda, Bosnia in Rationale for Libya Intervention

Clinton emphasized the humanitarian rationale for the U.S. military intervention in Libya, recalling instances from recent history when a lack of U.S. intervention had left hundreds of thousands dead.

Clinton said that the United Nations-backed military intervention in Libya "is a watershed moment in international decision making. We learned a lot in the 1990s. We saw what happened in Rwanda. It took a long time in the Balkans, in Kosovo to deal with a tyrant. But I think in what has happened since March 1st, and we're not even done with the month, demonstrates really remarkable leadership."

Clinton played out a hypothetical of what non-intervention by the United States might have looked like.

"Imagine we were sitting here and Benghazi had been overrun, a city of 700,000 people, and tens of thousands of people had been slaughtered, hundreds of thousands had fled and, as Bob [Gates] said, either with nowhere to go or overwhelming Egypt while it's in its own difficult transition. And we were sitting here, the cries would be, why did the United States not do anything?" she said

"Why -- how could you stand by when, you know, France and the United Kingdom and other Europeans and the Arab League and your Arab partners were saying you've got to do something," Clinton told Tapper.

In an interview on "This Week" in December, 2007, Clinton told George Stephanopoulos that she urged President Clinton to intervene in Rwanda during the 1994 genocide there.

Then-Senator Clinton said, "I believe that our government failed. … I think that for me it was one of the most poignant and difficult experiences when I met with Rwandan refugees in Kampala, Uganda, shortly after the genocide ended and I personally apologized to women whose arms had been hacked off who had seen their husbands and children murdered before their very eyes and were at the bottom of piles of bodies, and then when I was able to go to Rwanda and be part of expressing our deep regrets because we didn't speak out adequately enough and we certainly didn't take action."

The New York Times reported that Clinton, along with National Security aide Samantha Power and U.S. Ambassador to the United Nations Susan Rice, helped convince President Obama to take action on Libya. Rice, who worked on the National Security Council for President Clinton during the genocide in Rwanda, in which up to a million people were slaughtered, has expressed regret for not doing more to encourage intervention to stop the killing. Powers, formerly a journalist, wrote the seminal book on U.S. non-intervention during massive humanitarian crises.

The White House vehemently denied that Clinton, Powers and Rice were instrumental in pushing the President to approve the Libya intervention.

Clinton Says U.S.-Pakistan Relationship "Very Difficult"

Clinton made it clear that the U.S. relationship with Pakistan was not in an ideal place.

Tapper asked, "Has this relationship gotten worse in the last six months, U.S.-Pakistan?"

"Well, Jake, it's a very challenging relationship because there have been some problems. We were very appreciative of getting our diplomat out of Pakistan and that took cooperation by the government of Pakistan," she said, referring to the release of Raymond Davis, the American CIA contractor recently released after months in a Pakistani prison on charges of murdering two men in Lahore.

"We have cooperated very closely together in going after terrorists who pose a threat to both us and the Pakistanis themselves. But it's a very difficult relationship because Pakistan is in a hard position trying to figure out how it's going to contend with its own internal extremist threat," she said.

"But I think on the other hand, we've also developed good lines of communication, good opportunities for cooperation, but it's something we have to work on every day."

Worry About a Post-Saleh Yemen

Gates expressed worry in the interview about Yemen, after that Middle Eastern country's long-time President Ali Abdullah Saleh said he was willing to step down. Saleh was in talks Saturday to leave office after 32 years, according to The Associated Press. Widespread protests in Yemen have sapped Saleh's political support in recent days.

"Secretary Gates, you said this week we have not done any post-Saleh planning," Tapper said. "How dangerous is a post-Saleh world, a post-Saleh Yemen to the United States?" he asked.

"Well," Secretary Gates replied, "I think it is a real concern because the most active and, at this point, perhaps the most aggressive branch of al Qaeda -- al Qaeda and the Arabian Peninsula -- operates out of Yemen.

"And we have had a lot of counterterrorism cooperation from President Saleh and Yemeni Security Services," he said.

"So if that government collapses or is replaced by one that is dramatically more weak, then I think we'll face some additional challenges out of Yemen. There's no question about it. It's a real problem," Gates told Tapper.

In response to violence in Yemen last week, President Obama released a statement saying, in part, "I strongly condemn the violence that has taken place in Yemen today and call on President Saleh to adhere to his public pledge to allow demonstrations to take place peacefully. Those responsible for today's violence must be held accountable."