Perhaps some wordplay, force your debater to think it through.
Argument “The government shouldn’t legislate morality”
Response “Are you saying homosexuality is a moral choice, rather than a biological predisposition?”
Argument “The government has no business in the bedroom”
Response “We were talking about gay marriage, not gay sex. Sex between consenting adults is private. But marriage is a public act - the single most public act a couple may ever participate in.”
Argument “What two people do in the bedroom has nothing to do with you”
Response “Not true. Adultery causes deep scars, for example, and sex always complicates a relationship, especially if one of the couple is not ready for it emotionally. But we aren’t talking about the bedroom, but marriage itself, the bulk of which takes place outside the bedroom.”
Argument “Why are you against two people loving one another?”
Response “Again, we’re talking marriage. You don’t need to be married to love one another. Love is private. Love cannot be proven, nor does it need to be defended from inquiry. Love is how two people define it. But marriage is an institution. It has a particular form and dictates particular rules; fidelity, lifelong communion, common living. That’s even before a host of tax and legal ramifications have developed around it. In the churches - mine as well as others - marriage takes on a spiritual dimension as well. Perhaps it does for many who don’t consider themselves religious. But I plainly tell you that not all love must necessarily marry under Catholic vows for it to be love. However, those who choose to marry under such vows are held to them and should not think to change them or take them lightly. If you love another and cannot abide by the vows of a particular faith, don’t take them. Just love the other, even unmarried.”
Argument “We’re only asking for marriage equality”
Response “You can ask for equal treatment under tax and employment law for yourself and your spouse as husband-wife couples have currently. Beyond that, the law has no reach. My children have a mother and a father, yours have two of one and none of the other. My marriage doesn’t have to be defended as part of a school curriculum like yours does. I don’t have to make attempts to assert the normality of being married to my wife, while I don’t know if you’ll ever be able to say the same. I don’t say this to be mean but to be honest. No matter how great your love for your spouse, Your marriage is not the equal of mine, but a different entity.”
So-called “gay marriage” becoming the law makes anyone who disagrees with it a law breaker and therefore subject to punishment under the law.
It is a frightening development when government determines that expression of belief is criminal. Cases are most often made against an individual for denial of service under a public accommodation law (and the scope of what constitutes a public accommodation is wide enough to encompass nearly every public-serving entity), but I do think there’s merit in saying “You are a business. You serve the public. Serve the entire public.” What is problematic is how litigious we’ve become, and when a denial should result in a "I’m telling everyone I know … " but instead becomes a “You’ve denied my basic human rights by not making a wedding cake for my wedding!”
I don’t think we’ll ever get to:
And the government can begin to send people to jail for a so-called “hate crime” of not agreeing that homosexual behavior is normal or for refusing to send your child to Kindergarten class on the day when the school wants to teach the children that “gay marriage” is good. And the government would use this as justification for taking your children away.
Because that’s how you get law-abiding people to become revolutionaries.