But political junkies don’t swing elections. In fact, something like 25 percent of voters make their voting decisions after September, and anywhere from 10 percent to 20 percent will make their final choice in the last week.

This is why the polls have often swung wildly in the final weeks of a campaign. It’s how “Dewey defeated Truman” in 1948. It’s how a blowout Richard Nixon victory in 1968 turned into a squeaker. It’s how Gerald Ford closed a 10-point gap and actually had a lead in the final Gallup poll in 1976.

It’s how a toss-up race between Jimmy Carter and Ronald Reagan finished with a GOP blowout in 1980. It’s how Bill Clinton went from being up 9 in mid-September, 1992 to a tie with George H.W. Bush by the end of October.

It’s how George W. Bush went from being 10 points down in September 2000 to the 43rd president in January 2001. And it’s how the very same Bush “blew” the 11-point lead he enjoyed in late September 2004, defeating John Kerry by just 2 points.