This is a huge subject to cover, especially when talking about it through a Christian perspective. Where to start and where to end is very complicated.
First and foremost, as Christians, we cannot approach this subject as if being homosexual, lesbian, etc. is any worse or more unforgivable to God than any other sin. Simply put, sin is sin. Now, sexual sin in general (and in any form–––including pornography, infidelity, and the like), certainly can be seen as one of the most destructive, if not the most destructive of sins compared to some. Nevertheless, sin is sin and we will all be held accountable on the day of Judgement. Only with the blood of Christ covering us shall any human being be given an abundance of grace by receiving eternal life. In our personal lives, we must love everyone deeply as Christ loved, but we cannot agree or support the gay lifestyle. We must love the person and lead them to the Gospel, but we cannot condone the lifestyle.
Personally, I have no idea why the federal government is getting their noses into this topic. President Obama has every right to believe the way he does and I do appreciate him not making it an issue (to the point that he feels there needs to be a constitutional amendment for it). I also appreciate the fact that he is allowing state sovereignty on this issue.
What is sad about this whole issue is that it reveals the moral degradation of our culture. No matter what way the issue falls or how the government (whether federal or state) decides to go with it, it does not really matter on a grand scale. Only through the power of Gospel and working of the Holy Spirit on an individual’s life can someone truly change their lifestyle or change the way one thinks, especially with this issue. Our culture needs Christ, not government making laws.
With that said, some states do allow for civil unions to take place, but even that is not enough. I believe this issue is not about what technical rights someone may have, but this is about a group of people wanting to be accepted into the culture as normal and natural.
Similar to abortion, when an issue is made into law, there typically is a culture shift in opinions on the issue. Since abortion was made legal, it seems, especially over time, more and more people tend to think abortion is simply a necessary (and at times unfortunate) right of women. If gay marriage were to pass, particularly on a federal level, I believe the same type of culture shift would occur. I do not personally support gay marriage, but I could see an argument to be made for allowing civil unions when it comes to benefits and the like. Again, that will never be enough for most–––this argument has been made into an equality argument, as if gay rights are equal to the civil rights movement of the 60s.
As Christians, I do not believe we should support the government in their efforts to change the definition and meaning of marriage, but again, our main focus should not be on specific laws. We should look to challenge the notion out there that homosexuality is equal to race, but we have to do it through the Gospel, or honestly, it does not matter. It is not our opinion that is being espoused, but it is the command and values of our Heavenly Father through the revealing of His truth through Scripture. I do not believe this issue will affect the election very much, seeing as most people who adamantly support gay marriage are typically progressives (and vice versa).
President Obama, in my opinion, is simply using gay marriage as an election tool. I think the most pivotal issues will be about the economy including taxes, gas prices, stimulus packages and the like. The wars we are in and will potentially enter into will also be large I am sure. The big moral issues that will come about will be in regards to social justice with the economy, especially in Christian circles.