The Peace Party would claim the mantle of peace, which would be a tremendously strong position to work from. It's a name which is simple to say, which suggests inspiration and vision, and which speaks to people's highest ideals. Deep down, people are always hungry for the truth because only the truth is ultimately satisfying. And thus we bear an inspired message that people are hungry to hear, if only we can communicate it effectively. The message is that we'll ultimately either learn to live freely and peacefully together or not at all.
Libertine is shorter, sounds better, and is more provocative than Libertarian.
Because the word libertine already has a non-political meaning that's humorous and amusing, changing to the Libertine Party would attract greater attention from the media. I'm sure this would make the party a butt of jokes around the nation. In my opinion, the word libertarian is boring and stale. Changing to the Libertine Party would generate broader and more intense scrutiny by the media. It also has the potential to create much greater interest in the party by young people.