But that solution is already written into the Constitution, and you are advocating amending the Constitution to do the exact opposite of what you want done!
You want the Constitution Amended to force the States into accepting the Federal government's definition of marriage...whatever that may actually be, and whatever they may decide to do (and it may not even be the definition that you want!) rather than allowing the States the right to decide what they want to do!
Remember prohibition?
Enact Amendments to each State's Constitution, and make them fight fifty States.
Because the Federal government bases certain decisions and enforces certain laws based upon the definition of marriage. So long as that is true, the people have a right to determine that definition.
And we will have our say.