NCR has obtained a copy of the USCCB's proposed document on marriage (for their November meeting) which you can read here. Much of the document is taken up with the theology of marriage (marriage as a sacrament, as a sign of Christ's love, as a symbol of the Trinity and of the church), and some passages focus on the question of same-sex marriages, which prompts perhaps the strongest language of the 57-page document. Same-sex marriage, says the document, "harms the intrinsic dignity of every human person and the common good of society." NCR also has an editorial here. Read it all for yourself. But remember, it's only a draft.
Bishops' Marriage Doc Obtained by NCR