A colleague asked why people running hopeless campaigns continue taking people's money and clogging venues such as last night's Democratic debate?
The truth is that there are probably a number of reasons why lower tier candidates continue plodding along. Here are a few:
The Stroke of Luck Candidate
Some genuinely believe it's their time, the frontrunners will fade, circumstances shift, and fate propels them to glory.
e.g., Dennis Kucinich, Newt Gringrich (although he's unannounced but active), Steve Bloomberg, Michael Forbes
The VP Candidate
Some run with a realization that the presidency is not in the cards--at least not right away. What they're really trying to do build their brand and donor base so they can leverage it into a VP slot or Cabinet Secretary.
e.g., Jim Gilmore, Chris Dodd, Tom Vilsak, Duncan Hunter, Wesley Clark
The Training Candidate
Every election cycle there are a few candidates that wade into national presidential politics as part of a plan to run and win in a later cycle. Most have their best plans subverted by developments out of their control and never win the brass ring; while others find themselves as the nominee--or even as president-elect.
e.g., Michael Dukakis, Bill Clinton, Al Gore
The Advocacy Candidate
Some are use a presidential run to make a point, raise and supporters to do more of the same.
e.g., Tom Tancredo, Ron Paul, Al Sharpton, Ralph Nader
The Clueless Candidate
Some people run for reasons only they understand.
e.g., Mike Gravel, James Bond Stockdale