We are hearing a lot about how the current controversy in the Catholic Church is ideological in nature. As the media has it, "conservative Catholics" are attacking the pope while "progressive Catholics" defend him against the evil assault. This is ridiculous for many reasons, starting with the fact that the controversy is about sex abuse and cover-ups. It's got nothing to do with ideology. But this framing of the issue stems from an even deeper falsehood — that such a thing as progressive Catholicism, or progressive Christianity, exists or can exist.
The "conservative vs. progressive" dichotomy is most often cited with regard to sexual morality and homosexuality in particular. We are told that defense of sexual morality and condemnation of the homosexual act is a "conservative" position. Across all the churches and denominations, it is said that those who promote chastity and believe in the sanctity of the marital covenant are "conservative Christians." "Progressive Christians," on the other hand, take a more open-minded view of these topics. The obvious implication is that a Christian might look at the issue and settle on either side of it. But this is not possible. There is no "other side" within Christianity. The issue is not up for debate.
There cannot be a conservative/liberal divide on the basic moral teachings of Christianity. There is only the Christian understanding vs. the non-Christian understanding. A person who accepts and defends the moral truths of the faith is not necessarily "conservative." He is just Christian. A person who rejects those truths is not a "liberal Christian." He is not Christian at all.
I am not at the moment interested in discussing whether Christianity is right about homosexuality or human sexuality in general. The point is simply that Christianity does have a teaching on the subject, and, if you wish to be Christian, you can't disagree with it. The Bible clearly condemns the homosexual act repeatedly, including in 1 Corinthians 6:9-11, Romans 1:26-27, 1 Timothy 1:10, and all across the Old Testament, most notably in Leviticus and Genesis. And Jesus Christ is quoted in two Gospel accounts explicitly defining marriage. He teaches that marriage is when a "man" and "his wife" come together and "become one flesh." That is settled doctrine, right from the Son of Man Himself. It is not a liberal doctrine or a conservative doctrine. It is just truth. A Christian must accept that it is truth because it came from the One who Himself is Truth.
All in all, we are left with a clear, uncompromising, unmistakable consensus across both the Old and New Testament about the nature of marriage and the moral depravity of all unchaste sex acts, including the homosexual act. Every church for almost 2,000 years affirmed these teachings and no Christian theologian or thinker of any note found, or claimed to find, any "liberal" interpretation of the verses mentioned above. That is because no such interpretation can be found. We either affirm the Biblical view on this topic, or we throw the Bible out and Christianity with it. There is no option in between.
If you are a Christian with a "progressive" view of marriage and sexuality, then one of the following things must be the case:
1) You do not believe that the Bible is a reliable source for moral truth.
2) You do not believe what the Gospel says about Christ's own words.
3) You believe that Jesus was a man of His time who lacked a full understanding of marriage and sexuality.
If you have any of those opinions then the good news is that a lot of people agree with you. In fact, you have the same opinion of Scripture, Christian teaching, and Jesus Christ that all non-Christians do. You believe them to be unreliable, fallible, and entirely human. The bad news is that none of those opinions are even slightly compatible with Christianity. You cannot retain your Christian faith while questioning the divinity of Christ and the legitimacy of Scripture.
There may be a real conservative/liberal split when it comes to lesser matters. For instance, conservatives tend to favor more reverent and traditional worship styles while liberals favor modernized and secularized varieties. On this issue, we, as Christians, may take the liberal or conservative stance and have a discussion about it (though the liberal stance is wrong here as well). But there is no debate to be had about the fundamental moral teachings of the faith. We either accept those or we do not. And if we do not accept those, we do not accept the faith.