Pakistan will not go as far as Washington wants, and there's nothing the US can do about it: That's the sobering reality as the US tries to persuade a hesitant Pakistan to finish off the fight against terrorists. Expand the current assault against the Taliban? Pakistan has made clear that will happen only on its own terms. US officials acknowledge that so far they haven't won the argument that militants who target America are enemies of Pakistan, too. The US has offered Pakistan $7.5 billion in nonmilitary aid plus more to help Pakistan go after terrorists. The assistance is intended to help Pakistan speed up its fight not only against internal militants, but also against Al-Qaeda and Taliban leaders hiding near the border with Afghanistan. Pakistanis are deeply suspicious of America's power and motives, making it difficult for their leaders to accede to Washington's pressure in public, lest they look like US puppets. US officials say that while Pakistani officials cooperate more in private, there are definite limits. The US wanted Pakistan to move forces deeper into the tribal belt before winter. It didn't happen, and might not at all. A senior US diplomat hinted at a separate agreement that would allow the US itself to take on some of the hidden war against Pakistan's militants. Speaking on condition of anonymity to discuss sensitive talks with Pakistan, the diplomat said last week that more US action is expected against the Haqqani network, led by longtime resistance fighter and former US ally Jalaluddin Haqqani. His network, based in the Waziristan tribal area in northwest Pakistan, reportedly has strong ties with Al-Qaeda and targets US forces in eastern Afghanistan from across the border. The diplomat said the stepped-up US action would come with Pakistani support, but would not elaborate on the potential cooperation. Pakistani officials claim they have targeted the Haqqani leadership, albeit unsuccessfully, and will go after the network when the time is right. Some US officials believe that, others don't. Military officials say the Haqqani problem illustrates how the United States sometimes needs Pakistan more than the other way around. The US military now counts the Haqqani network as the single gravest threat to US forces fighting over the border in Afghanistan, and badly wants Pakistan to push the militants from their border refuges. But the Pakistani answer seems to be that unless and until the Haqqanis threaten Pakistan, they won't be a priority. Adm. Mike Mullen, chairman of the US Joint Chiefs of Staff, was the latest US official to make the case in a visit to Pakistan's capital last week. More than most US officials, Mullen has cordial, long-standing relationships with Pakistan's generals, the strongest power base inside the country. Despite those ties, Mullen's quiet effort met with a polite noncommittal from his hosts. Mullen advises patience and humility in dealing with Pakistan, a view not shared by some leading Republicans in Congress. Mullen said Pakistan doesn't get enough credit for the push since spring against militants in the Swat valley and South Waziristan. “Too many people eagerly and easily criticize Pakistan for what they have not done,” Mullen said Sunday, days after Pakistan's military leaders took Mullen on a tour of a reclaimed Swat. “When I go to Swat, and look at what they did there on the military I think it's pretty extraordinary.” Most of the groups aligned against the US are in North Waziristan, a tribal area not pressed hard by Pakistan's army. The only firepower directed at militants there comes from American missile-loaded drones. Mullen told students at Pakistan's National Defense University that the US is concerned about what it sees as a growing coordination among terrorist networks in and around Pakistan. “I do not, certainly, claim that they are great friends, but they are collaborating in ways that quite frankly, scare me quite a bit,” Mullen said last week. He did not come out and say Pakistan needs to expand the fight against militants. But his point was clear. In an exchange of letters over recent weeks, Obama asked for more cooperation and Pakistan's president, Asif Ali Zardari, pledged some additional help, US officials said. The officials spoke on condition of anonymity to describe private correspondence. Zardari, reflecting the views of Pakistan's powerful military, said his government will move against militants that attack US forces when it is able to do so, the officials said. That leaves ample room for Pakistan's civilian leaders to pursue their own agenda – and on their own schedule. Without additional pressure from inside Pakistan, the only other option is for the US to finish the fight against terrorists on its own. But Pakistan doesn't allow outright US military action on its soil. Mullen seemed to recognize that when he told the military students that he knows the US is perceived as acting in its own interests almost at any cost, so it can hardly ask others not to put their own needs first. “Sometimes that gets lost on us,” he said.