War on Terror as Political Science Problem
Democracy is a highly imperfect method of getting good government. One thing that makes it work better is the general sense that if good things happen to a country, incumbent politicians will benefit from that whereas if bad things happen, incumbents will suffer. That often leads to election results that aren't really "deserved" since Jimmy Carter didn't cause the 70s oil crisis and Bill Clinton didn't cause the 90s tech boom. But it does keep the incentives where they belong -- insofar as things are under the control of politicians, the politicians try to make good things happen.
But not the post-9/11 GOP. Their political meal ticket is a population terrified of terrorism, and nothing whips that terror up quite like actual terrorism in London, Madrid, wherever. The result is a political party that simply can't adopt policies designed to ratchet-down the level of danger and anxiety.