After the terrorist attacks of September 11, 2001, most insurance companies canceled their insurance coverage for terrorism. According to President Bush, "More than $15 billion in real estate transactions have been canceled or put on hold because owners and investors could not obtain the insurance protection they need." As a result, the federal government stepped in to provide coverage for up to $90 billion in claims. Using the principles of insurance, explain why insurance companies might decline to insure property against terrorist attacks. Explain whether or not you think the federal program is an appropriate form of social insurance.