WASHINGTON - A key US senator, who said last week after a trip to Afghanistan that the Taliban are stronger, now believes the militant group can be defeated if Pakistan complemented American efforts.Senator Dianne Feinstein, the Democratic chairwoman of the Senate Select Committee on Intelligence, told ‘Fox News Sunday’ that Pakistan is key to defeating the Taliban in both countries and expressed frustration that Pakistan has failed to deprive them of a safe haven in the rugged mountain areas along its Afghan border."Militarily, I think the Taliban are not going to beat us," she said. But the Taliban "have a safe harbor in Pakistan and the Pakistanis are doing nothing to abate that safe haven," Feinstein said."So, it's a big problem and I think that the key to Afghanistan is really action by Pakistan with respect to the Haqqani, with respect to the Taliban, and a new solidarity hopefully between our two countries to eliminate safe havens for terrorist," she said.Feinstein, however, expressed delight at the positive changes she witnessed in Afghanistan, especially, on girls' education front."I'll tell you, there were two things that came through as very positive from our visit. The first was, according to General Allen (Commander of US and NATO forces in Afghanistan), 362,000 mark of trained Afghan military will be met. He said they are doing very well."They are in the lead in many missions and they are carrying it out with alacrity and with talent. So, that's good."What "the Taliban has done is insinuate itself in a shadowy presence, with shadow governors. They controlled over a third of the land which people live. They expanded into the north, into the northeast," Feinstein said."And while we were there in one province, they closed 14 schools in 17 districts and then they killed five education officials and wounded others," she told Fox News."And now, there's this latest assassination of someone who's been a leader in the Peace Council," she said.Gunmen shot dead a top Afghan peace negotiator in the capital Kabul on Sunday, dealing another blow to attempts to negotiate a peace deal with the Taliban.Maulvi Arsala Rahmani, 68, was one of the most senior and important members on Afghanistan's High Peace Council, set up by President Hamid Karzai two years ago to liaise with the insurgents. The Taliban denied involvement in the killing.What this does is demonstrate to many of us that the Taliban is just waiting to come back" when US troops leave the country over the next few years, Feinstein said.The Taliban "are taxing the poppy in the south to the tune of $125 million, which in 2011 - this is the United Nations figure - went to support their operations.""The question comes 'can they come back?'" said Feinstein, who visited Afghanistan as part of a congressional team last month. She said Karzai had assured her he would not allow the Taliban to return to power.Feinstein said assurance by the commander of U.S. and NATO forces in Afghanistan, General John Allen, that the number of trained Afghan troops will reach 362,000 was ‘very positive’.