Devout Catholic against legalizing same sex marriage. I find you can only evangelize people one step at a time. You can proclaim God to the atheist, and Christ to the theist, Catholicism to the Christian, and traditional Catholicism to the cultural Catholic- but if you try to jump straight to "No Gay Marriage" without all the foundational philosophy that goes into it, then you just end up derailing people on their spiritual journey.
I make no secret of my Catholicism in my public life, but I also do my best to not turn people from Christ through clumsy proselytism.