My understanding is that same-sex marriage is a federal law, which Roe never was - it was a SCOTUS decision regarding the right to privacy. Feel free to correct me (not you cultprogs - you tards don't know sh*t about **** so butt out).
The Republicans lose me hard when they start meddling in people's private lives. I get kicking Roe back to the states, but how will they do that with marriage? If some state decides nah, what happens to all the married gays and lesbians in that state?
This is how the GOP lost so many voters - getting involved in chit that's none of their damn business. They need to focus on things that affect ALL Americans, not things that affect NO Americans.
The short answer to your thread title question is, I think... possibly, but not very likely.
That said, no, same-sex marriage isn't legal nationally because of a federal law but rather because of a Supreme Court decision - Obergefell v Hodges (2015). The legality of same-sex marriage is in much the same posture as that of pre-viability abortion was before the Dobbs decision.
Marriage and abortion have always been understood to be state issues. Some federal regulation has been passed regarding both issues, but the federalism question (i.e. whether states or the federal government had the constitutional authority to regulate in a given area) hasn't really been the issue. Roe, e.g., wasn't about federalism and, despite the commonly pushed narrative, Dobbs didn't return the abortion issue to the states in a federalism sense. Obergefell wasn't about federalism. Even Windsor - the decision which struck down §3 of the DOMA, which had effectively defined marriage for federal law purposes as not including same-sex marriages - wasn't decided on federalism grounds, though it necessarily touched on federalism issues in reaching its Fifth Amendment Equal Protection conclusion.
So, first step, marriage and abortion are firstly and primarily areas in which states have authority to regulate. But as with all regulation - federal and state - such is limited by various individual rights guarantees found in the Constitution. So the question becomes, does the regulation the states have chosen violate the Constitution in some other (i.e. not related to federalism) way? When it comes to the states, most individual rights protections are found in seven - rather vague - words found in the Fourteenth Amendment: privileges or immunities, due process, equal protection.
The questions always revolve around: What do those words mean? Is a given right found or not found in those words? Free speech (again, as it relates to state level restrictions), religious exercise, rights to contract, rights to possess firearms, bodily autonomy, freedom to travel, etcetera, all must be found in those vague words. And such is the case when it comes to supposed abortion and marriage rights.
So, anyway, as with abortion (up to varying points in pregnancies) same-sex marriage was legal in some states before a Supreme Court decision effectively finding that it's a constitutional right (based on the vague words of the 14th Amendment). It was illegal and/or unrecognized in other states. Obergefell changed that just as Roe changed the landscape with regard to abortion, the latter having significantly restricted the ways in which states could regulate abortion. States still had the authority to regulate marriage and abortion, but in doing so there were certain things which they weren't - based on Supreme Court decisions - allowed to do. Similarly, states can regulate firearms and speech. But in doing so there are (not so) certain things which they aren't allowed to do.
Will there be a Dobbs-like decision regarding same-sex marriage, effectively overruling Obergefell? Perhaps. That's one of the possibilities liberals have floated in order cultivate political support. For various reasons I think it's more a tilted-at windmill than a real threat.
