President Nader?

I heard yesterday that Ralph Nader is entering the Presidential race. I am bothered by this, not because I don't believe in the beauty of our democracy, but because all the other candidates have campaigned so hard to make it to this point and he just wanders in (hey...I could have waited and used this as my Heads or Tails post...) at the last minute...

I guess here is the other thing that irritates me. He knows he can't win...at least I think he knows that. I feel that is a bit of a slap in the face to the cadidates who have worked hard to earn votes so far...he is going to most likely take away votes from two candidates who can legitimately win. Plus, in a race that will be close anyway (I am guessing), all votes count.

Does this mean that I could enter the race as an independent if I wanted to? What exactly are the rules about that?