My advice is do some research about nutrition and vegetarianism. Offer to help plan menus and cook some nights. Usually parents are more amenable when the child does the research and presents some facts. If you help with menu planning and cooking, whoever cooks in your family will LOVE you and vegetarian-phobic members may be more willing to try some new and delicious food!
When I went veg about 8 years ago, I found The Vegetarian Times magazine helpful with meal planning and delicious recipes. They publish books for various age groups on becoming veggie and starting out. I purchased the general starter one. It did help me.
As for the political aspect, it is very complex indeed. There is no end to the articles. Do a little footwork on the internet. Neither candidate is a vegetarian and there are quite a few issues that are more important to the general population. It's a lesser of two evils debate, as usual.
http://www.washingtonpost.com/wp-dyn...2004Oct21.html http://www.johnkerry.com/communities/sportsmen/ http://www.georgewbush.com/News/Read.aspx?ID=2930