Never argue for any particular position; present a series of facts and ideas, then allow your audience to come to their own conclusion. Nobody likes being told what to think, but most people take great satisfaction in joining up the dots for themselves.
Some people might still call you a Nazi, but your obvious reasonableness will be a near-infallible shield; they'll look silly and you'll look dignified.
Study marketing. Major corporations have invested billions in developing powerful persuasion methods, so loot their arsenal. You can sell a political position in exactly the same way as a can of fizzy drink, with immeasurably greater success than someone using the traditional techniques of political rhetoric.