I have felt for some time that the primary tactic in the right's battle to deny marriage equality will be a perceived threat to religious freedom. But read this.
It's a brief from findlaw.com that establishes the case that religious freedom and marriage equality are tied to each other in case law.
Freedom isn't the same for everyone, so you have to make accommodations: "Just as the free exercise of religion is useless to an Orthodox Jew if it only protects his right to observe Sunday as the Sabbath, so too the right to marry is an empty guarantee if it only protects a lesbian’s right to marry a man."
There are going to have to be accommodations on both sides, because we're in this freedom thing together.