One problem with this is that your
vote really doesn't count. Unfortunately the
republic structure of the
United States voting system makes your vote important to the
electoral college who in turn are supposed to represent you.
The only reason I can think of that might actually motivate people who actually advocate change through political process is that the Green Party is on the eve of getting some well deserved funding. Nader is not going to be president but at least his campaigning might well establish the Greens in the United States.
Then again, I'm pretty cynical about reformist politics in general. Bah humbug!