[radikal]

States can change their own laws to recognize whatever they want. Yes, and the corollary is that other states are not required to recognise their laws. Look at this from the other side. If massachusetts were required to have the same laws as other states, they never would have been permitted to change their law.

It's a double edged sword. Yes, states are free to have their own laws, but they are not free to force their laws on the other states.

The standard procedure is to recognize marriages/unions from other jurisdictions unless there is legislation specifically to the contrary (eg, State A gay-marries Ben and Ned, Ben and Ned move to Arkansas which has legislation banning gay marriage, so their marriage is not recognized in Arkansas). Which is exactly the case in Louisiana. So, your point here is that Massachusetts laws should take precedence over Louisiana laws in LA.