Interviews leave many basic questions unanswered about the mission's duration, point and endgame.
The president's top foreign officials on Sunday said unrest in Libya posed no imminent threat to national interests, and were unable to answer exactly how long the U.S. mission in Libya would last.
Defense Secretary Robert Gates and Secretary of State Hillary Rodham Clinton hit the Sunday talk shows one day before President Obama is slated to address the nation, but their interviews left many basic questions for Obama to answer: How long will the mission in Libya last? What is the mission? And what exactly is the endgame for the U.S.?
The officials' comments came hours before NATO officially agreed to take command of operations in Libya, the State Department announced Sunday.
On the ground in Libya, meanwhile, the rebel forces pushed the troops loyal to Libyan dictator Moammar Gadhafi back, taking Brega and nearly recapturing Ras Lanuf. Both places are important because of oil refineries there, media reported.
When pointedly asked on ABC's This Week if the Libyan mission would end by the end of the year, Gates said he did not believe anyone knew how long the mission in Libya would last, despite reports that officials within the Pentagon believe the mission could last several months or longer.
"I don't think anybody knows the answer to that," Gates said.
Gates also said the Libyan invasion was not a "vital national interest" to the United States, but said the future of Libya was key to successful democratic revolutions in other Middle Eastern countries.
"It was not a vital national interest to the United States, but it was an interest…you had a potentially significantly destabilizing event taking place in Libya that put at risk potentially the revolutions in both Tunisia and Egypt," Gates said.
The point that Libya was not a military threat to the United States may be obvious, but Gates's statement could open up a new line of attack from Republicans.
Sen. Dick Lugar, R-Ind., the ranking member on the Senate Foreign Relations Committee, questioned that exact point Sunday.
"I don't believe we should be engaged in a Libyan civil war. The fact is we don't have particular ties with anybody in the Libyan picture. It is not a vital interest to the United States," Lugar said on NBC's Meet the Press. "American interests are not at stake," he said.
Another emerging Republican argument contends that U.S. military involvement with Libya must continue until Gadhafi is removed.
Former National Security Adviser Stephen Hadley and former National Security Agency Director retired Gen. Michael Hayden, both officials under the George W. Bush administration, said the removal of Gadhafi must be the ultimate U.S. goal in Libya, or the country will risk destabilizing the region and the prestige of the United States.
"That was the informal contract," Hayden said. "We're in this until he goes away.
"If we fail in Libya, we will teach Bashar Al-Assad and leaders in Tehran: if you kill enough of your own citizens, you stay," Hayden said. "Maybe the most important thing we can do in Syria is to succeed in Libya."
Former Defense Secretary Donald Rumsfeld echoed that point Sunday.
"I think the goal has to be that Gadhafi leaves. My personal view is that once you're involved, you have to recognize the prestige of the United States is at stake," Rumsfeld said on ABC's This Week.
But Gates said the ultimate U.S. military mission did not include the removal of Gadhafi, because regime change can be "very complicated."
"What you're seeing is the difference between a military mission and a policy objective," said Gates on CBS. "You don't, as a military campaign, set as a mission something you can't achieve," Gates said.
Democratic Sen. Carl Levin of Michigan, the chairman of the Senate Armed Services Committee, also deflected statements that the U.S. role in Libya would not end until Gadhafi is removed from office.
"It depends on the circumstances that exist at that particular time," Levin said on CNN's State of the Union. "There are other means of removing Gadhafi besides militarily."
Clinton was pushed on her and President Obama's opposition, when they were both in the Senate, to former President George W. Bush's invasion of Iraq without seeking congressional approval.
"We would welcome congressional support," Clinton said. "But I don't think this kind if internationally authorized intervention…is the kind of unilateral action that either I or President Obama were speaking of several years ago."
Congress has not authorized the Libyan military action. Levin is holding a hearing in the Senate Armed Services committee Tuesday on the Libyan mission.
Despite violent retaliations by Middle Eastern dictators against their own people, Clinton said the United States is not planning a military role similar to the mission in Libya.
"Each of these situations is unique," said Secretary of State Hillary Rodham Clinton on CBS' Face the Nation, after saying the U.S. is not going into Syria or other Middle Eastern countries.
"Certainly we deplore the violence in Syria," Clinton said, "but the situation in Libya…the international community moved with great speed, in part because there's a history here."
Clinton defended the U.S. role in Libya by saying no policy position is perfect.
"Every decision that we make is going to have pluses and minuses," said Clinton.
"Imagine we were sitting here and Bengazi had been overrun and tens of thousands of people had been slaughtered…the cries would be 'Why did the United States not doing anything?'"