Justice Kennedy wrote the Majority Opinion: (About the Same Sex Ruling)
Under the Due Process Clause of the Fourteenth Amendment, no State shall “deprive any person of life, liberty, or property, without due process of law.” The fundamental liberties protected by this Clause include most of the rights enumerated in the Bill of Rights.
Now the question–Are 2nd Amendment rights among those “protected by this Clause”?
As the Swing voter (Justice Kennedy) could also consider the Mentioned above for "National Reciprocity".
Something to think about.