I could see this working really well if you did it with opposing charities, e.g. RNC vs. DNC. The charities wouldn't even need to endorse it, necessarily. Could be huge.
We at Tipjoy had similar ideas for a big conference coming up. The problem is that it would be around 3-1 for the left. That's just the profile online.
Comments welcome about the site design! How can I get the activity twitter updates to attract more users? How do I keep users returning once a day?