[Labyrinthos]

Right, and it's a states' issue and a personal issue. But it is not a Constitutionally delegated issue of the Federal Government.

It could be a federal constitutional issue under the Full Faith and Credit Clause and Equal Protection Clause (rational basis test).

[PapaNew]

It could be a federal constitutional issue under the Full Faith and Credit Clause and Equal Protection Clause (rational basis test).

These would be issues to enforce the Constitutional requirements between the states, not excuses for the federal government to itself decide on issues like marriage or abortion or the million other things they have no business deciding.