Overturning the Obergefell ruling would be a tall order according to Dale Carpenter, a constitutional law professor at Southern Methodist University who is in a same-sex marriage himself and generally identifies as a Republican. Test cases, he said, could evolve from some of the religious-based challenges in Oregon, Colorado and Mississippi, and Texas legislators are flirting with bills that would require state officials to enforce the state’s Bill of Rights, which defines marriage as something that “only” occurs between a man and a woman. Nonetheless, Professor Carpenter said it was unlikely the Supreme Court would reopen debate or reverse itself in the next four years — even if the makeup of the court became increasingly conservative.

Laurence H. Tribe, a constitutional law professor at Harvard Law School, called the Obergefell ruling, “a decision as close to being etched in stone as any Supreme Court decision in recent years.”

Still, those facts have not kept some gay and lesbian couples from feeling anxious about their future under a Trump administration — fears they are sharing on Twitter and Facebook, and on websites like Reddit, Curve and Vice. In a Vice article headlined “Why I’m Marrying My Partner Before Trump Can Take My Rights Away,” Zach Brooke, a freelance writer in Wisconsin, wrote: “The morning after Donald Trump was named president-elect, my partner and I calmly discussed how his presidency might affect us personally. We concluded that the possibility of future same-sex marriage restrictions is very real, and that if we wanted to get married, the time is now or never.”

Mr. Brooke added, “We don’t know how dark the future will be for LGBTQ individuals in the four years to come, but we do know it will be harder to dissolve existing marriages than to prevent new ones, and we’d rather not take our chances.”

What seems to trouble some of these gay and lesbian couples the most are not the specific positions taken by Mr. Trump, but those of his more conservative supporters.