WASHINGTON (Agencies) - The US shares part of the responsibility for Pakistans 'unhealthy civil-military relationship by supporting the countrys dictators for most of the last century, a top American expert has said. Despite our commitment to democracy, we have provided little backing to Pakistans civilian leaders over the decades. The US is not wholly responsible for Pakistans unhealthy civil-military relationship, but it is not innocent of responsibility, Bruce Riedel, a former CIA analyst, wrote in a forward to the book 'The Future of Pakistan. Brought out by Brookings Institute, a Washington-based think-tank, the book is a compilation of a series of articles by eminent scholars from the US, India and Pakistan, including Stephen P Cohen, C Christina Fair, Shuja Nawaj, and Kanti Bajpai. For most of the last century the United States has been a partner of Pakistans military dictators, enthusiastically embracing all four generals who have ruled Pakistan. Presidents from Kennedy to Bush have invited them to the White House for state dinners and intimate consultations, Riedel wrote in the book that hit the stands this month. We have jointly embarked on great clandestine projects such as the U2 base in Peshawar in the late 1950s; Henry Kissingers secret trip to Beijing from Islamabad in July 1971; the covert war against the Soviet Union in Afghanistan that helped destroy the USSR in the 1980s; and the battle against Qaeda in this century. All were done with the involvement of Pakistans military dictators, he wrote. Riedel said three years ago President Barack Obama had called him and asked him to chair an urgent interagency review of policy toward Pakistan and Afghanistan. He (Obama) said that no issue on his foreign policy agenda was more important than the fate of Pakistan, which he rightly has described as the epicentre of the global terrorist threat today, he said in the forward to the book, adding that Pakistan is a country of growing, indeed crucial, importance to the United States and to the rest of the world. The terrorist attack on Mumbai, India, in November 2008, just days after Obamas election, was the first major international crisis on the newly-elected Presidents watch. He said the killing of Osama bin Laden by the US forces in a secret operation in Abbottabad without the knowledge of the Pakistani government and Army was a defining moment of the Obama Administration. Pakistan, Riedel said, is much more than just a problem for US counter terrorism policy. No country is more important to the future of Americas relationship with the Muslim world. It is also has the fastest-growing nuclear arsenal in the world, producing more weapons today, including tactical nuclear weapons, than any other country. It may soon have the fourth-largest nuclear arsenal in the world, outgunned only by the United States, Russia, and China. No country is more important with respect to nuclear arms control, nuclear proliferation, and nuclear war, he wrote. Noting that US and Pakistan have had a very conflicted relationship for over half a century, Riedel said Americans have come to see Pakistan as a deceitful partner.