You can always be sued, by anyone, for anything. The question is whether they can win. The best way to cover yourself is to be completely forthright about what you are doing. Make sure that anyone who buys the book knows exactly where their money is going, i.e. what percentage is going towards the political party and what percentage is going elsewhere. Also, don't be too loose with the term "non profit". Does the organization qualify as a not for profit entity under both IRS and state regulations and laws? Has it registered as one?