The debate about constitutional amendments concerning same-sex unions really should not come down to competing ways of the interpreting the Bible, but some of the claims in recent letters about various passages in the Bible make it hard to resist another response.
1. The story about Sodom in Genesis 18 targets the sin of raping strangers, not consensual, committed sex of any kind. Elsewhere in the Bible (Isaiah 1:10-17; Jeremiah 23:14; and Ezekiel 16:49), the sin of Sodom is variously described as luxury, complacency, opulence, neglect of the poor and needy, failure to champion the oppressed, the widow, and the orphan, having hands full of blood, walking in lies, committing adultery, and strengthening the hands of evildoers - not homosexual activity.
2. Leviticus 18 and 20 are chapters concerned with maximizing population growth and also with setting Israel apart from her Canaanite neighbors, who included homosexual behavior as part of their fertility religion. Idol worship therefore was the context, and it remains so in Romans 1, which Paul wrote from Corinth, where homosexual and heterosexual activity was part of the practice of religious cults (7,000 male and female prostitutes staffed one temple to Aphrodite). Homosexual acts connected with idol worship are included in an extensive list of sins manifesting idolatry in Romans 1.