More than 100 days after the United States and NATO allies launched what was supposed to be a quick air campaign in Libya, Pentagon officials concede that the effort has little strategic value for the U.S., and the alliance's desired outcome there remains unclear. What's become an open-ended conflict, military officers and experts say, illustrates ill-defined U.S. objectives, the limits of relying solely on air power and the lack of diplomatic tools to broker an end to Moammar Gadhafi's regime. The NATO effort is almost exclusively an air campaign, which is designed to ground Gadhafi's warplanes and strike at his weapons sites. But at times it appears that NATO has tried to topple Gadhafi, which experts said demands ground forces, a larger air campaign and a clear plan for who will lead Libya in the aftermath of the regime. The hope was that by only using air power, NATO would reduce the costs and risk to troops. But experts say that air power only rarely leads to regime change and isn't always cheaper. NATO believed that without Gadhafi's air power, the rebels could claim control of the country within weeks - as quickly as the regimes fell in neighboring Egypt and Tunisia. But instead, the rebels now control less ground than they did when the NATO intervention began.