Gadhafi maintains control of the Libyan military, including its air force, while the rebel force remains largely unorganized and poorly armed.
But the White House quickly countered Clapper's claim, saying the "dynamic" abroad is already shifting and military strength alone won't dictate the outcome of the conflict.
"Director Clapper stated what is true, that Col. Gadhafi is hunkering down -- we all know that," White House press secretary Jay Carney said. But "the dynamic in Libya is changing by the hour and the day. Everything we are doing ... is designed precisely to change the dynamic and put pressure on Col. Gadhafi."
National security adviser Tom Donilon challenged Clapper's assessment, saying it failed to take into account the "motivation" and "incentive" of the Libyan rebels.
Looking at the situation in the Middle East "through a multidimensional lens ... you get a very different picture," Donilon told reporters.
"The people of Libya are determined to affect their future," he said, insisting that pro-democracy interests will prevail.
Senior administration officials have still not recognized Libya's Transitional National Council as a legitimate replacement for Gadhafi's regime, a move that would allow the council to take control of $30 billion in Gadhafi's assets now frozen by the United States. France offered the council official recognition Wednesday, but U.S. officials said they're still talking with other opposition groups.
Libyan diplomats who broke with Gadhafi have been pressuring Obama to recognize the council and will press their case at a rally in Washington on Friday.
But the Obama administration ran afoul of the rebels' supporters Thursday when Secretary of State Hillary Clinton announced that the U.S. was cutting off relations with the Libyan Embassy in Washington, a move Carney said is meant to shut out Gadhafi's diplomats. Aly R. Abuzaakouk, who is backing the rebels, said the move is a blow to the opposition movement.
"It is shocking to get such a step from our administration, after the president said that Gadhafi has lost legitimacy," Abuzaakouk said. "It's really an unwelcome step."
Obama is also resisting calls from the Libyan diplomats and rebel supporters to establish a no-fly zone over Libya to shut down Gadhafi's air force, saying he's waiting for NATO to decide. NATO officials meeting in Brussels, Belgium, on Thursday said they would put off a decision on the no-fly zones until March 15.
For now, NATO will move warships in the region closer to Libya to increase surveillance and ensure Libya's compliance with a United Nations arms embargo.
Defense Secretary Robert Gates remained wary of any military action following the NATO meeting, saying such a move would require U.N. approval.
"If there were to be a need for enforcement," Gates said, "there would need to be a new United Nations Security Council resolutions even for that purpose."