The 9/11 terrorist attacks marked a change in tone within the USA from one of domestic tranquility to one of war footing and counter intelligence. If you had been in charge of US counterintelligence,...

Case scenario
For preventing 9/11 terrorist attack, I think that controlling immigration and domestic surveillance, both would prove crucial factor in the strategy of preventing such terrorist attacks. The main reason behind recommending both the strategies is the assumption that it would be quite difficult for USA to adopt and consider single factor. It would be justifiable to adopt a balancing strategy of controlling immigration and domestic surveillance.
Under controlling immigration, USA legal framework and regulatory authorities would keep a check on border laws and immigration. This strategy require making border laws and regulations quite strict and tougher for keeping a strict check on the people entering in country. Prior 9/11 terrorist attack, it appears...