On ABC's "This Week," Gates said some NATO officials suggested it would take three months "but people in the Pentagon think it could be far longer than that."
View full sizeDefense Secretary Robert Gates, left, seen with Joint Chiefs Chairman Adm. Michael Mullen earlier this year.By BRADLEY KLAPPER
WASHINGTON (AP) — Ahead of President Barack Obama's national address on Libya, top officials of his administration claimed major strides were being made in bolstering rebels fighting Moammar Gadhafi's forces but acknowledged the international operation could drag on for months.
Lawmakers of both parties voiced skepticism over the length, scope and costs of the mission.
"We have to a very large extent completed the military mission in terms of getting it set up. Now, the no-fly zone and even the humanitarian side will have to be sustained for some period of time," said Defense Secretary Robert Gates.
Asked for how long on NBC's "Meet the Press," Gates said, "Nobody knows the answer to that question." But he said sustaining the no-fly zone would take "a lot less effort" than establishing it. He said the Pentagon was planning to shift some of its resources to European and other countries pledging to take on a larger role
On ABC's "This Week," Gates said some NATO officials suggested it would take three months "but people in the Pentagon think it could be far longer than that."
Gates and Secretary of State Hillary Rodham Clinton made the rounds of network talk shows — in interviews taped Saturday and aired Sunday — to promote the administration's case before Obama's speech on Monday night.
The North Atlantic Treaty Organization, which took over enforcing the no-fly zone from the U.S. late last week, seemed likely to expand its air mission on Sunday to assume command of American-led air strikes against Gadhafi's ground forces. The U.S. is eager to hand off responsibility for air strikes to the alliance.
Clinton told CBS' "Face the Nation" that no decision had yet been made on the whether to arm rebels seeking Gadhafi's ouster. So far, "results on the ground are pretty significant," she said.
The secretary of state said she recognizes that many Americans are concerned about the role of the U.S. — already burdened by wars in Iraq and Afghanistan — and that "the president will speak to the country Monday night to answer a lot of those concerns."
Sen. Richard Lugar of Indiana, the top Republican on the Senate Foreign Relations Committee, sounded some of those concerns in advance of Monday's 7:30 p.m. EDT speech.
Lugar said the president still has not developed a plan spelling out the extent of future U.S. involvement in Libya and how objectives are to be achieved. Nor, Lugar said, has there been a debate over how to pay the tab and how much it could total.
"There has to be objectives and a plan and an agreement that we're prepared to devote the military forces but also the money," Lugar said on "Meet the Press."
"Who knows how long this goes on and, furthermore, who has budgeted for Libya at all?" asked Lugar, who in the past has been supportive of Obama on most military issues.
Sen. Carl Levin, D-Mich., the Armed Services Committee chairman, was broadly supportive of the president's steps so far. "It is a flyover which is succeeding. It has set Gadhafi back. He's on his heels now," Levin said on CNN's "State of the Union."
Still, Levin said it remains unclear how long the air campaign will have to last if Gadhafi clings to power.
"The people of Libya can remove their dictator. But we are not the ones to remove him," Levin said, echoing the administration's insistence that the Western military mission is not to target Gadhafi, even though Obama has said the autocratic ruler of more than four decades must go.
Meanwhile, Sen. Joe Lieberman, I-Conn., told "Fox News Sunday" that the United States, in the actions it and other Western nations have taken in Libya, has sided with "the mass of people yearning to be free within the Arab world."
"I think the world has made a clear statement in Libya heard by both the Arab people and the Arab dictators elsewhere in the region," Lieberman said.
In particular, he mentioned revolts in Syria against President Bashar Assad's government. Assad, Lieberman said, "is getting a clear message. If he turns his weapons on his people and begins to slaughter them, as Gadhafi did, he's going to run the risk of having the world community come in and impose a no-fly zone and protect civilian population, just as we're doing in Libya."
However, the administration wasn't willing to go as far. Clinton declined to say if the U.S. might be willing to enter other conflicts where governments attack their own people and told CBS that it was too early to talk of intervention in Syria, where security forces have opened fire on protesters amid nationwide unrest. Unlike Gadhafi, Assad is a "different leader" and many members of Congress who have visited the country "believe he's a reformer," Clinton said.
Former House Speaker Newt Gingrich, eyeing a run for the 2012 GOP presidential nomination, defended his current skepticism over the no-fly zone in light of his comments several weeks ago that the United States should immediately impose one — unilaterally if necessary.
He said his earlier comments came before Obama acted. Now, Obama has confused the situation, he suggested. Gingrich said he's against a no-fly zone if it just allows Gadhafi to hang on for months.
"The goal should be to get rid of Gadhafi. That should be communicated publicly so Gadhafi's forces lose their morale," Gingrich said on "Fox News Sunday."
"I hope the president tomorrow night will be dramatically clearer than he has been up until now. I hope the president will say, first of all he is consulting the U.S. Congress, not just the Arab League and United Nations," he said.
In their taped interviews, Gates and Clinton defended the narrowly defined U.N. mandate to prevent atrocities against Libyan civilians and said the U.S. had largely accomplished its goals.
"We have taken out his armor," Gates said, adding that the U.S. soon would relinquish its leading role in enforcing a no-fly zone and striking pro-Gadhafi ground targets intent on violence.
Clinton said "we're beginning to see, because of the good work of the coalition, his troops begin to turn back toward the west — and to see the opposition begin to reclaim the ground they had lost."
Libyan rebels seized back two key oil complexes and pushed west toward Tripoli on Sunday, gaining momentum after international airstrikes that tipped the balance away from Gadhafi's military.
The coastal complexes at Ras Lanouf and Brega were responsible for much of Libya's 1.5 million barrels of daily exports, which have all but stopped since the uprising began Feb. 15.
U.S.-led airstrikes earlier allowed anti-government forces to recapture the key eastern city of Ajdabiya.
NATO's top decision-making body was to meet Sunday to expand its enforcement of the no-fly zone to include air strikes against Libyan ground targets.
Obama has come under deep bipartisan criticism from lawmakers upset that he hadn't sought greater congressional input on Libya.
The lack of clarity on that question reflects a worry for lawmakers clamoring to hear fuller explanations from the administration on why the U.S. was embroiling itself in another Muslim conflict and what the ultimate goals of the intervention are.
Clinton and Gates insisted that the objective was limited to protecting civilians, even as they hoped the pressure of concerted international penalties and isolation might strip away Gadhafi's remaining loyalists and cause his government to crumble.
"One should not underestimate the possibility of the regime itself cracking," Gates said on "Meet The Press."
Even after a week of air strikes, Pentagon officials say forces loyal to Gadhafi are a potent threat to civilians. Defense officials are looking at plans to expand the firepower and airborne surveillance systems in the military campaign, including using the Air Force's AC-130 gunship armed with cannons that shoot from the side doors, as well as helicopters and drones. Gates said the U.S. could supply rebels with arms if the administration makes such a decision.
With the United States already trying to exit long wars in Iraq and Afghanistan, the administration has gone to great efforts to define the Libya operations as limited in scope and duration — and necessary to prevent Gadhafi from possibly massacring civilians while his forces were reaching the rebel stronghold of Benghazi.
Asked if the Libyan conflict posed a threat to the United States, Gates said it was "not a vital national interest" but he insisted that the situation nevertheless demanded U.S. involvement. With tenuous democratic transitions under way in the neighboring countries of Tunisia and — more important to the U.S. — Egypt, allowing the entire region to be destabilized was a dangerous option.