Yes, Congress *can* Constitutionally codify Obergefell
These homophobes and 10th Amendment mouth breathers are at it again, asking Congress enumerated power on the Respect For Marriage Act, accusing a violation of the oath of office and saying its a states rights issue.
No state shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any state deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws. - Fourteenth Amendment to the Constitution.
From Britannica.
Obergefell v. Hodges, legal case in which the U.S. Supreme Court ruled (54) on June 26, 2015, that state bans on same-sex marriage and on recognizing same-sex marriages duly performed in other jurisdictions are unconstitutional under the due process and equal protection clauses of the Fourteenth Amendment to the U.S. Constitution.
So, its been established Obergefell was voted in favor for due to Equal Protection and Due Process.
Heres one more nugget from the Fourteenth Amendment.
The Congress shall have power to enforce, by appropriate legislation, the provisions of this article.
So, does Congress have the Constitutional authority to pass the Respect For Marriage Act? Absolutely.