Brandan promotes the idea that marriage defined by the government should be theologically neutral. However, Boling and Lenow don't see morality and legality as mutually exclusive. The government's decision is going to be conducive to someone's morality, why not the Christian's?
Brandan balks at the idea that we should Christianize the nation. He thinks its not Christ-like, nor are Christians consistent when arguing that they should. If they were, they would seek to make drunkenness, adultery and lying illegal.
Brandan maintains that the government is not in the sacrament business. But they kind of are. Most Christians consider marriage to be a sacrament, the government regulates marriages, ergo, the government is in the sacrament business. Therefore, Christians feel like they need to push for their definition of marriage. Telling a conservative Christian that the government can take a theologically neutral stance on marriage is like saying the government could take a theologically neutral stance on baptism or the Lord's supper. It does not compute. If the government were to give benefits to those who were baptized or took the Lord's supper, then we would have the same issue with those sacraments. Therein lies the crux of the matter. What we need is a "third way" when dealing with marriage and the government. If government wasn't involved in marriage, this wouldn't be as much of an issue. Actually, Brandan would prefer that the government not be involved in marriage at all, but they are, so he's seeking to change change it's definition of it - to what he feels is a theological neutral one.
Our founding fathers set up this nation so that each citizen is a sovereign. We should think of America as an alliance of over 350 million itty bitty kingdoms, and the purpose of the government is to protect the persons and property of those kingdoms, nothing more. Going back to Brandan's point about drunkenness, adultery and lying: The government does take a stance on those issues when is comes to protecting the persons and property of others. Those in power always want a democracy mob rule, but those not in power always want the minority protecting republic. If most conservative Christians were honest, they would want to Christianize the nation, but since the SCOTUS decision they are finally starting to see the wisdom of getting the government out of the marriage business. It cuts both ways though, Progressive Christians want to Christianize the nation as well when is comes to helping the poor and access to free health-care. You will love your neighbor whether you want to or not.
I believe before any discussion of the morality or legality of same-sex marriage can be had, a discussion needs to be had on the morality of whether each citizen can be a sovereign individual. Sadly, I think most Americans would say that there can't be and will continually try to enforce their values onto others. I recently listened to the "Should you impose your values on others?" episode on this podcast. On my RE2 podcast, we discussed Al Mohler's difficulties with libertarian ideas. Also, Ben Lewis has a nice article on the Kim Davis fiasco over at The Great Fiction.
Boling and Lenow try to get to Brandan's rational basis for his government definition of marriage, but they usually frame it in terms of polygamy or incest. This puts Brandan on the defensive, and he sees it as a straw-man and/or slippery slope argument. Boling and Lenow's point though, is not whether polygamy or incest would happen, but rather if they could be justified by using Brandan's rational framework. Brandan would say that it would not, but we don't get many details as to why.
Brandan gives aspects of his rational framework, but Boling and Lenow don't really pick up on it or pursue it. Incestuous marriages are "unhealthy" because of the genetic effects on offspring. But what if they don't have kid's, does that make it okay? Bestiality is "obviously" wrong. Well, it wasn't that long ago that homosexuality was "obviously" wrong. What's the basis? Brandan also argues that we should change the definition of marriage because the current definition harms people and causes them pain. Is the government expected to stop all harm and pain that can be experienced? My point is not to disagree with Brandan necessarily, but I would have liked to have seen his rational framework explored a bit more. His hermeneutical approach to the Bible may give us additional insight.
Duo Experiencia Et Communitas
Both experience and community (if my Latin is right) is what Brandon promotes in understanding the Bible. He is correct in noting that Protestants tend to get nervous whenever someone speaks of experience as their basis for understanding truth. TGC recently released a video on Sola Experiencia. But Brandan sees the Scriptures as evolving. He says the Old Testament view of God is not the same as the New Testament, and there are other differences as well. Brandan looks to experience instead of the propositional statements of the Bible, but he calls for the tempering of ones experience with community. One may feel God is telling them one thing, and another person feels God is telling them another, but it is within community that things like that can be sorted out. I'd like to hear some real world examples of that. Also, what if God is telling one community one thing and another community another thing. How do you sort that out? You can listen to Brandon talk about his thoughts on the Bible here.
Here's another debate on homosexuality, although it's not much of a debate. Brandan is much more focused here and stays tight on his talking points. He's reluctant to engage Dr. Michael Brown in debate, and I can't say that I blame him after watching Dr. Brown steamroll Matthew Vines (word of advice: don't using the Socratic method when debating Dr. Brown)