theories can be broadly divided into three main forms: LIHOP ("Let it happen on purpose") – suggests that key individuals within the government had at least some foreknowledge of the attacks and deliberately ignored it or actively weakened United States' defenses to ensure the hijacked flights were not intercepted. Similar allegations were made about Pearl Harbor. MIHOP ("Make/Made it happen on purpose") – that key individuals within the government planned the attacks and collaborated with, or framed, al-Qaeda in carrying them out. There is a range of opinions about how this might have been achieved. Others – who reject the accepted account of the September 11 attacks are not proposing specific theories, but try to demonstrate that the U.S. government's account of the events is wrong. This, according to them, would lead to a general call for a new official investigation into the events of September 11, 2001. According to Jonathan Kay, managing editor for comment at the Canadian newspaper National Post and author of the Among the Truthers: A Journey Through America's Growing Conspiracist Underground, "They feel their job is to show everybody that the official theory of 9/11 is wrong. And then, when everybody is convinced, then the population will rise up and demand a new investigation with government resources, and that investigation will tell us what actually happened." Theories Foreknowledge Conspiracy theorists claim that action or inaction by U.S. officials with foreknowledge was intended to ensure that the attacks took place successfully. For example, Michael Meacher, former British environment minister and member of Tony Blair's government, said that the United States knowingly failed to prevent the attacks. Suspected insider trading Some conspiracy theorists maintain that just before 9/11, an "extraordinary" amount of put options were placed on United Airlines and American Airlines stocks and speculate that insiders may have known in advance of the coming events of 9/11 and placed their bets accordingly. An analysis into the possibility of insider trading on 9/11 concludes that: This study was intended to address the "great deal of speculation about whether option market activity indicated that the terrorists or their associates had traded in the days leading up to September 11 on advance knowledge of the impending attacks." In the days leading up to 9/11, analysis shows a rise in the put to call ratio for United Airlines and American Airlines, the two airlines from which planes were hijacked on