The opinion was written by a judge appointed by G.W. Bush, who has a fairly conservative voting record up to now.
Interestingly, the opinion does not find that there is a constitutional right to gay marriage; in fact, it explicitly holds that there is no such right.
What the decision holds is that the definition of marriage is a state function, not one delegated to the federal government. It goes on to hold that, because Massachusetts recognizes gay marriages, the federal government has no right to treat people who are married under Massachusetts law as if they were unmarried.
Or, we could say that, this decision is that the federal government has no right to define marriage.
But is that really true? If I recall correctly, a Supreme Court decision in the late 1800s upheld a federal law which bans polygamy. It was a case dealing with Mormon plural marriage.
It just seems to me that, legally, the federal government should have a definition of marriage, because many areas of federal law depend on marital status. If this decision means that the federal government has to accept any definition of marriage, then I guess I’m lost on the reasoning.