1. Lawrence v. Texas, was one of many cases (and statutes) over the last 200+ years by which the Americans legalized virtually all types of גלוי עריות. There is overwhelming public support for this and it is unlikely to be changed. Even if the courts were to allow such laws, there would never be public support among the goyim to criminalize consensual behavior. We Yidden are used to the goyim acting in way we don’t approve.
2. Given the above, which began in the early 18th century (when they rejected the common law definition of marriage as involving one man, one woman, to the exclusion of all others, lasting for life with no possibility of divorce), it is inevitable that the Americans would redefine marriage based on the idea of two people who marry for love as opposed to be people forming an economic partnership to raise children. As we follow halacha, this really has no impact on us (anymore than a statute regulating how much cheese goes into a cheeseburger).
3. Roe v Wade, on abortion is different, since even goyim object to murder, and the scientific evidence of the last 40 + years reject that upon which Roe v Wade was based. Back then, it was believed by scientists that the baby was just a mass of insentient tissue until shortly before birth, and modern science has shown otherwise. In America there is not overwhelming support for “abortion on demand”, but there isn’t enough support for a constitutional amendment to change the law.