My parents, whom I am currently visiting, had CNN turned on the other day in the background. There was a discussion of a Bush campaign stop in Ohio, and I've heard it said that no Republican in the last --- years has won the presidency without winning Ohio, and therefore Ohio is a crucial state for Bush.

How useful are these past trends anyway?

In 2000, I remember hearing a lot about California: nobody had won the presidency without winning California since Carter in '76. This comment was followed up with an assesement of how crucial Bush's efforts in California were. And yet Bush somehow managed to win the presidency without winning California after all.