Linda,
You don't think interracial marriage is a sin. There were Christians of the time who did. You think homosexual marriage is a sin. There are Christians today who don't. Of course, I still don't see what <I>any</I> of this has to do with me, a non-Christian. You are once again conflating your religion's morality with secular legality... making juice from the apples and mixing it with the motor oil, shall we say.
Listen: The sin in question is not gay <I>marriage</I>, it is gay <I>sex.</I> Do you think gay sex should be illegal? If not, then why campaign against gay marriage?