But your opinion should not become a law that blocks my roommate from falling in love and marrying someone he wants to marry.
First of all, I'm not sure how you got off on law and marriage. But either way it isn't very relevant. Even if a country has a legal code such that it can allow gay unions under the label "marriage" this would not make them legitimate marriages, in so far as God has established the covenant. And Christians are never at liberty (from a moral vantage point) to contradict God and call good that which he calls evil.
But entertaining the question of laws and marriage, Why shouldn't my "opinion" become legally enforcible? It's not clear how you're using "opinion" here. An opinion can simply be a belief or it can be a certain type of belief. For instance, you may think an opinion is a belief that we don't have good reasons for entertaining. In that case, I agree that beliefs which we don't have good reasons for entertaining ("opinions") should not be a basis for law. But I disagree that my belief is an opinion in this sense.
So I think I have good reasons for my belief and I think that some beliefs which have good reasons can become or influence laws. Of course not all well grounded beliefs should be laws or influence laws, but I don't see why you can simply assume that this is one of those beliefs that should not be in light of the fact that, up until just a few years ago virtually every state already had marriage laws that were related to and congruous with my belief.
And no, it's not pedophilia or beastiality.
I already preempted this straw-man and I already pointed you to where I preempted it. You haven't interacted with that at all, you've just repeated a remark that I already responded to in anticipation, before you ever even made the remark!
It's an adult consensual relationship that, yes, is based on love.
That it is consensual is irrelevant. Pedophile relationships between a 60 year old and a 13 year old can be consensual. To say it is based on love is to contradict Scripture which considers it an exchange of "natural relations for those that are contrary to nature" (Rom. 1:26). It's just as absurd to say that a pedophile loves his young boy or a rapist his victim. It is a perversion of love and to try and honor it with the title of "love" (let alone to try and honor the perverse union as a "marriage") is to degrade the very virtue that is love (and the covenant that is marriage).
But religion + law = no bueno.
Really? So how about irreligion + law? Why would religion and law be a bad mix but irreligion and law be a good mix? Why would secularism + law be a good mix? Do you have any idea how many assumptions are built into your statement there? For example, if homosexuality is wrong, then no state can legitimately legalize it or make it a right since, as John Locke argued, no one has the right to do wrong.
Or take for example an Aristotelian view of the state where "Statecraft is soulcraft" (as George Will and others have put it). In this instance, Francis Beckwith points out that "the state or government, by its policies, procedures and actions, places moral ideas in the social and legal fabric of a political regime, and that these ideas serve to shape the quality of its citizens' character" (Politics for Christians 36).
In fact, in one sense, we may say politics is simply ethics applied to the society. So says Simmons:
"What is distinctive about political philosophy, however, is its prescriptive or evaluative concern with justifications, values, ideals, rights, obligations--in short, its concern with how political societies should be, how political policies and institutions can be justified, how we and our political office holders ought to behave in our public lives. . . .Political philosophy can thus be aptly characterized as a branch or an application of moral philosophy"
(Political Philosophy 2).
But if this is the case its far (very far) from clear why religion shouldn't inform politics (or public policy). In fact, as a Christian you should think that religion (the Christian religion) has very important and even indispensable insights into the formation and maintenance of law. At least this is what one of our earliest Supreme Court Justices thought:
“Indeed, the right of a society or government to interfere in matters of religion, will hardly be contested by any persons, who believe that piety, religion, and morality are intimately connected with the well being of the state, and indispensable to the administration of civil justice… It is, indeed, difficult to conceive, how any civilized society can well exist without them. And, at all events, it is impossible for those, who believe in the truth of Christianity, as a Divine revelation, to doubt, that it is the especial duty of government to foster, and encourage it among all the citizens and subjects… This is a point wholly distinct from that of the right of private judgment in matters of religion, and of the freedom of public worship, according to the dictates of one's conscience… at the time of the adoption of the Constitution, and of the amendment to it, now under consideration, the general, if not the universal, sentiment in America was, that Christianity ought to receive encouragement from the State"
(Supreme Court Justice Joseph Story, commentary on the US Constitution; emphasis mine).
In so far as the law concerns itself with moral issues and legislates from moral principles, Christians should have something to contribute, not just as citizens, but as Christians.
But I've argued all this at great length elsewhere and I don't have the interest currently to go through it all again. In fact I've already spent too much time with you here. However, Beckwith gets to the heart of the issue in your statement when he says:
"...too often in our contemporary culture, theologically informed beliefs are not considered a legitimate claim to knowledge. This is why, for example, it is enough for some commentators to call a belief 'religious' in order to treat it as an item that cannot be reflected in our laws or be part of our political regime. For we would consider it strange if someone dismissed another's political views because they were judged by lawyers, politicians and editorialists as 'history,' or 'science' or 'journalism.' If an idea is labeled 'religious,' it is essentially being called nonsense. This understanding is so much a part of our public culture that many people think nothing of it when it is presented to us in policy discussions."
(ibid 77)
Beckwith has hit the nail on the head and I've never debated a professing Christian who said religion cannot or should not inform law who had any good reasons (especially no historically informed reasons from our American heritage) outside of simply shouting ever louder their mantra that religion just can't inform politics... because it just can't! Why? Well, because that's what their politics teacher taught them in public education! That's what they heard on the news! And so on and so forth. Of course the atheist can just say "because your religion is a joke," and while I disagree, it's at least a better reason than any Christian could give.
A law blocking gay marriage discriminated us...
Right, all laws which prohibit actions discriminate. Rape laws discriminate against rapists. Pedophile laws discriminate against pedophiles. Murder laws discriminate against murderers. What's your point?
This isn't a "Christian issue." It's an American issue.
False dichotomy.
Believing it is sinful is one thing, but forcing your religion upon people by law is wrong.
I wonder what the basis of this belief is. What's the basis of your belief that forcing your religion upon people by law is wrong?
But eitherway, prohibiting homosexual unions is not forcing religion upon people. It is forcing (in a sense) morality... but then a lot of laws force morality and so your statement would be obviously false that it is wrong to force morality.
But also, I pose this question.... So it's okay for a man and a woman who don't love each other to get married, but it's not okay for a woman and woman who REALLY do love each other to get married. I'm pretty sure Jesus wouldn't approve of the first...
So Jesus wouldn't approve of an arranged marriage where the couple obviously hasn't had the time to cultivate love? I find that highly implausible. It's okay for a man and woman to marry who do not yet love each other so long as they make a serious vow to cultivate that love and commit themselves to each other. It's not okay for a woman and a woman to get married, not simply because they cannot "REALLY" love each other (just as a pedophile could never REALLY love a 13 year old boy), but because marriage is only properly constituted between a man and a woman.