As libertarian Christians, we recognize that the cultural normalization of non-traditional sexual and family relationships deviates from God-given norms ordering creation---norms calling for sexual relations and family structures to reflect divine design. This includes lifelong monogamous unions between one man and one woman for procreation, nurture, and mutual support, as revealed in Scripture, as well as the valid calling to faithful singleness and celibacy exemplified by the Apostle Paul in 1 Corinthians 7, where he presents singleness as a gift that allows undivided devotion to the Lord.
Through redeeming grace in Christ, we are enabled to align our lives with these norms amid cultural shifts, while common grace allows even the unregenerate to conform externally to some degree. Our primary duty, therefore, is personal and communal faithfulness: modeling biblical sexuality, marriage, and faithful singleness in our households and churches, teaching and discipling others, and engaging in gracious evangelism that turns hearts to the true God rather than idols.
We view society as a network of diverse relations with distinct jurisdictions (families, churches, voluntary associations) that should coordinate through self-government, not as a monolithic whole. Thus, we oppose using civil governance---limited to punishing aggression (initiated coercion against persons or property)---to enforce conformity on non-aggressive moral issues.
Rather than pursuing legal prohibitions or mandates, we advocate liberty, allowing individuals to choose freely while bearing natural consequences, and we resist state violations of property rights or the non-aggression principle.
Our ultimate response is the persuasive power of the gospel: speaking truth in love, building voluntary communities that uphold God's norms, and trusting his sovereignty to renew culture through transformed lives---never through force or monopoly power.
This question is from Faith Seeking Freedom: Updated & Expanded, available in paperback, PDF, and Kindle.
Great summary of the principle and biblical perspective missed by so many Christians.