Soon after Pakistan launched its offensive against the Taliban this spring, President Asif Ali Zardari declared that the mission would go beyond pushing the Islamist militia out of the Swat Valley. 'We're going to go into Waziristan,' he said. More than two months later, that still has not come to pass. Instead, the planned invasion of South Waziristan, a Taliban and al-Qaida sanctuary along the Afghanistan border, has been delayed by the refugee crisis spawned by fighting in Swat, an overstretched military unwilling to let its guard down with India and the difficulty in isolating the Taliban commander Baitullah Mehsud, according to Pakistani and American officials. Pakistan's military has blockaded the tribal district and bombed it from the air, and it insists that the ground assault will proceed. But as the clock ticks, military analysts worry that fighting in the mountains will be more difficult as the weather turns cold in the fall. The delay has raised questions about Pakistan's commitment to waging war against Taliban fighters the state has nurtured in the past. 'It's an insane dream to expect anything different from the Pakistani government,' said Ali Wazir, a South Waziristan native and a politician with the secular Awami National Party. 'The Taliban are the brainchildren of the Pakistan army for the last 30 years. They are their own people. Could you kill your own brother?' Mehsud is believed to be responsible for the assassination of former prime minister Benazir Bhutto, as well as many of the recent suicide bombings in Pakistan. American officials, however, said they have not urged Pakistan to launch the operation because of the scope of problems in the Swat Valley, where 2 million refugees were displaced by the ongoing military operation there. 'Baitullah Mehsud is a dreadful man, and his elimination is an imperative. However, the first imperative is to secure the areas the refugees are going back into,' Richard Holbrooke, the U.S. envoy to the region, said in an interview. Although Holbrooke said it could be beneficial to have simultaneous offensives -- the U.S. Marines on the Afghanistan side of the border and the Pakistani army in the tribal regions to the east -- the greater concern is the unfinished business elsewhere. 'Why would I push them to start an offensive when they have 2 million people they have to protect first?' he said. The Pakistani military operation against the Taliban has unfolded in three phases, starting with the Frontier Corps paramilitary force in April moving into areas around the Swat Valley, the former tourist destination where the Taliban seized control. The following month two Pakistani divisions, or about 40,000 soldiers, led a ground operation into the valley. They have since regained control, although fighting continues and the Taliban leadership there remains remains largely intact. The third, and most difficult, phase was to be a ground operation into South Waziristan. But the offensive in Swat pushed some two million people from their homes and fighting there damaged hundreds of schools, homes, and businesses. The military now must orchestrate the return of thousands of refugees each day along with rebuilding and trying to prevent the Taliban from returning, as it has done in the past. The Taliban overwhelmed the police before the operation and residents are skeptical about whether the military can keep control. American officials are concerned that the Pakistani military might not stay in Swat long enough to ensure residents' safety. 'Failing to hold in Swat would be a calamity,' said a U.S. official in Pakistan, who spoke on condition of anonymity. 'I hope they're thinking about it in terms of a plan and not on a timetable.' One Pakistani diplomat said American officials are not happy with the level of coordination involved in providing money and services to the returning refugees. 'In their heart of hearts I think they feel that Pakistan will mess up the repatriation,' the diplomat said. 'They feel ... probably they'll go overboard, they won't resettle them, and you'll have a potential quicksand where you'll breed another strand of terrorist resistance.' Pakistani officials insist that they are focused on the refugees and don't want to rush into opening new fronts against the Taliban. Pakistan has already launched two operations into South Waziristan in recent years that failed to dislodge the Taliban. Since 2007, more than 2,200 Pakistani soldiers, police and intelligence officers have been killed in Swat and the tribal areas, and more than 5,300 have been injured. 'We would not like to do anything haphazardly. If you open so many fronts at the same time, then the danger is you will not achieve success on any front. So we would like to move with utmost circumspection,' said Foreign Ministry spokesman Abdul Basit. The tribal areas are 'a different ballgame and we need to understand how difficult it is.' Part of the reason the Pakistani government is wary about launching the Waziristan operation is there is little appetite to remove more troops from the 140,000-strong force that mans the eastern border with India. Two brigades have already left to join the Swat operation. 'That leaves us very little,' a Pakistani intelligence official said. Fighting in South Waziristan also poses a much greater challenge than in Swat. More than 400,000 people live in the tribal district, which is a bit larger than Delaware. Baitullah Mehsud commands about 10,000 to 12,000 fighters, including 4,000 foreign fighters, according to Pakistani intelligence officials. He pays his foot soldiers $60 to $80 a month, higher than the average local policeman's salary. Al-Qaida, meanwhile, has increased its focus on uniting Taliban and other Islamist jihadi groups in the fight against Pakistan, betting its success on the survival of the Taliban, according to intelligence officials. 'It will be longer and bloodier,' another intelligence official said of the fight against Baitullah Mehsud. 'He's been made into someone 10 feet tall.' Mehsud's stature has grown in part because of recent decisions by other Taliban commanders, such as Maulvi Nasir and Hafiz Gul Bahadur, who once cooperated with Pakistan but have announced their intention to fight security forces. Their representatives said they have been outraged by missile strikes from unmanned American aircraft. Instead of being able to rely on rival Taliban commanders to assist the army, the drone attacks have unified them against the state, intelligence officials said. Staff writer Karen DeYoung in Washington and special correspondent Haq Nawaz Khan in Islamabad contributed to this report. 