ON MONDAY, the Obama administration achieved one of the president’s principal goals in Libya: withdrawing U.S. warplanes from the fight against Moammar Gaddafi. In his speech last week explaining his decision to support an air campaign, Mr. Obama said that after leading initial strikes, U.S. forces would transition to “a supporting role”; in practice, that has meant the grounding of AC-130 and A-10 Warthog planes that had been pounding the tanks, trucks and artillery of the Gaddafi forces.

The unusual ceding of U.S. military leadership has served to reinforce Mr. Obama’s strategy of lowering America’s profile in the Middle East and sharing the burden of operations like Libya. The question is whether it is advancing more tangible U.S. aims in Libya — which according to Mr. Obama are protecting civilians.

The early results are not encouraging. On Tuesday, rebel forces were once again pushed back from the front line in eastern Libya by rocket and artillery barrages. Reuters quoted opposition fighters as saying that air support had slacked off noticeably. That followed statements Monday by the foreign policy director of the anti-Gaddafi Transitional National Council, Ali al-Essawi, who was quoted by the New York Times as saying that since NATO took command of the air operation over the weekend, “there’s a delay in reacting and lack of response to what’s going on on the ground.”

Such results would only be logical. No other NATO country deploys aircraft with the effectiveness of the AC-130 and A-10, which were designed for air-to-ground attacks on targets like tanks. Command by NATO means more disputes over how intensive strikes on the Gaddafi forces should be; members such as Turkey have objected to wide-ranging assaults. NATO briefers say that 30 percent of the regime’s ground forces have been destroyed. But that is not nearly enough damage to end the military stalemate.

Mr. Obama has said that the aim of the air campaign is not regime change, which he said can be accomplished by other means. The administration has dispatched an envoy to meet the rebel transitional government, along with CIA teams to help with communications and other logistics. In the past few days there have been encouraging signs that Mr. Gaddafi’s support is weakening, including the defection of his foreign minister. And U.S. planes are said to remain on call if NATO commanders need them.

Still, the dangers of the military stalemate for the United States increase with each day it lasts. The greater the disorder in Libya, the greater the chance that extremist forces, including al-Qaeda, will push aside the pro-Western figures who now lead the opposition. Secretary of State Hillary Rodham Clinton said a month ago that “one of our biggest concerns is Libya descending into chaos and becoming a giant Somalia.” And the longer the fighting continues, the more harm will come to civilians.

Mr. Obama said last week that because of his grounding of U.S. planes, “the risk and the cost of the operation . . . will be reduced significantly.” That may be the result in the short term. But if the withholding of American resources enables Mr. Gaddafi’s survival in power, the long-term consequences will be the reverse of the president’s promise.