Since marriage exists, it is not necessary to have a law upon a marriage. However, the government made marriage as a law for many legal reasons involved. Gay couples should have the same privilege, nothing more or less, just a simple equal, nothing special -- just everybody does, they get married!
Remember, the interracial marriage became an issue because of skin -- politics went mayhem! Whites tried to redefine the marriage. They had to complicate and made more laws on marriage.
Now, you can see this history over again, and gay marriage became an issue because of gender-based. What happened? Politics went nuttier off the chart than ever. Hetero tried to redefine the marriage - they shovel the morale down everybody's throat and slam gay people down harder. Do we deserve a slam-down? NO! Do we deserve a morale-shoving-down-throat? NO! We are merely humans and have capability to love whoever we choose.
Does this Romeo and Juliet familiar to you? Trying to run your life and telling you to be whatever they want you to be. What happened to the Shakespeare's saying, "Know thyself." I don't need a religion shoveling down my throat because it is not a love or peace, thus, religion is threatening me because they want to remove my rights, they want to remove my will away. I would say, screw them! I have a right to live. I have a right to love whoever I love. I have a right to marry whoever I want. Rights, rights, rights, rights -- how dare you try to remove my right away! Therefore, you can see why everybody is fighting to have the government to grant a marriage for gay people. Why complicated to grant a right while marriage is exisiting. That's really ridiculous. So, lawyers activated the US Constitution Amendent 14th to grant equal rights, equal protection, equal due process, equal, equal, equal, equal... do I need to keep saying equal? Hetero doesn't recognize "equal" because of the religion belief. So, there you go.
I thank God and I thank the US Constitution, I thank God for 14th Amendment, I thank God for 1st Amendment, and I thank US Congress for protecting my rights, my due process, my freedom, free from religious persecution.
Google "Separation of Church and State." Google Search has 1,640,210 results. I am sure that you would not have a problem finding it.