WASHINGTON, March 27, 2011 -- Former Secretary of Defense Donald Rumsfeld said today that if Gadhafi remains in power in Libya, it will damage the prestige of the United States. He compared the possible scenario of Gadhafi staying in power in Tripoli to the U.S. and coalition forces not removing Saddam Hussein during the 1991 Gulf War, though he refused to take a firm stand on whether U.S. military action in Libya was the correct move for the Obama administration.

In an exclusive interview on "This Week" with ABC News' Senior White House Correspondent Jake Tapper, Rumsfeld said, "the fact is we are involved" in Libya. "And the prestige of the United States is involved."

"Think back to the Gulf War in the early 1990s," said Rumsfeld, who served as George W. Bush's defense secretary from 2001-2006. "Saddam Hussein, when it was over, said he had fought the mother of all battles and President George Herbert Walker Bush was gone, Margaret Thatcher was gone, and he was still in office. And the implication of that was that he had defeated the United States," he said.

"We are involved," Rumsfeld said from Pensacola, Florida. "Let there be no question: we're now involved in Libya. And if Gadhafi stays on, he will feel he has fought the mother of all battles against the United States and it will be damaging to us just as our demeanor in Somalia was damaging, the situation in Lebanon was damaging and that will embolden others of his ilk," he told Tapper.

He also explained that the question of Gadhafi's longevity as leader of Libya had rippling effects. "If you put yourself in the shoes of the rebels," he said, "they wonder whether or not the coalition has an interest in Gadhafi leaving. There's a great deal of ambiguity about that."

"Gadhafi's forces wonder whether Gadhafi will be leaving – and that same ambiguity affects their decision-making," he said. "Until that's clarified, it seems to me, we'll have a much more difficult time. I think the goal has to be that Gadhafi leaves.

Rumsfeld: "Confusion" Reigns

Rumsfeld also used the word "confusion" six times to describe the United Nations-backed military effort in Libya. "The first thing you have to do," Rumsfeld told ABC News' Senior White House Correspondent Jake Tapper, "is recognize…the mission has to determine the coalition. The coalition ought not determine the mission."

"If you go into something with confusion and ambiguity about what the mission is – and we've heard four or five different explanations about why we're there – and that is the root of the problem. The confusion that comes from that," Rumsfeld told Tapper.

"Confusion about what the mission is, confusion about who the rebels are, confusion about whether or not Gadhafi should be left in power, confusion about what the command and control should be," Rumsfeld said.

The former defense secretary, who served in that position under both Presidents Gerald Ford and George W. Bush, said he thought the coalition involved in the Libya mission did not compare favorably to the coalition President George W. Bush put together to fight the "global war on terror."

"The coalition that is in place with respect to Libya is the smallest one in modern history," Rumsfeld said. "We had over 90 countries in the global war on terror that President Bush and Colin Powell put in place. We had dozens of countries involved in Afghanistan, dozens of countries involved in Iraq. … And still, the Democrats were alleging that it was President Bush was a unilateralist. It's nonsense," he insisted.

Libya Intervention Right Move for U.S.? Gates Mum

Tapper asked him, "are we doing the right thing in Libya?"

Rumsfeld evaded the question by stating the facts. "Well the first thing one has to say is that we have U.S. military forces involved and everyone has to be hopeful that it turns out well," he said.

"I'm wondering," Tapper asked later in the interview, "if you had been secretary of defense as Gadhafi's troops stormed into Benghazi, and Gadhafi himself threatened no mercy, and there was a very real fear of a mass slaughter, what would you have recommended to the president?" he asked.

"Well, I wasn't there, so I can't answer that question," Rumsfeld replied. "I will say that I think that President Obama and Secretary Clinton are both experiencing the differences from serving in a legislative branch and then serving in executive positions. The perspective is enormously different. And I think you can almost see them transition in their thinking and in their handling of this," he said.

Rumsfeld recently came out with a new memoir, "Known and Unknown."