Will they respect State Sovereignty?

The Massachusetts Supreme Court clarified a question put forth by state legislatures concerning the gay marriage ruling from last summer: is a civil union enough? The court's answer: no- only marriage will do it. (The court agrees with Jonathan Rauch in this online TNR debate on gay marriage)
The court decision cannot be appealed to the US Supreme Court because it is based on state law. Massachusetts lawmakers will be soon considering an amendment to their Constitution.
So, if no amendment passes there, will folks in DC attempt to step in? If Bush proposes federal legislation to affect the Massachusetts marriage laws, what happens to the State sovereignty so supposedly valued by Mr. Bush? Would Rehnquist allow such a federal control to pass?
Consider Bruce Fein in the Washington Times (representing the traditional, federalist position)(context: defending nomination of Bill Pryor):

State sovereignty over traditional local matters was embraced for multiple reasons. The science of government is the science of experiment. Political wisdom is more likely to be discovered through experiments in 50 different state laboratories than by lead-footed trial and error in one national laboratory. State experimentation, moreover, is less risky than a national gamble. A progressive icon, Justice Louis D. Brandeis lectured in New State Ice Co. vs. Liebman (1932): "To stay experimentation in things social and economic is a grave responsibility. Denial of the right to experiment may be fraught with serious consequences to the nation. It is one of the happy incidents of the federal system that a single courageous state may, if its citizens choose, serve as a laboratory; and try novel social and economic experiments without risk to the rest of the country."
...State experimentation is frustrated when Congress enacts a nationwide rule, whether within or without its constitutional authority. Statesmanship thus militates in favor of congressional deference unless states have been proven unfit to address or correct an evil. The latter circumstance is exemplified by the 1964 Civil Rights Act and the 1965 Voting Rights Act, both necessary to overcome a century of odious racial discrimination. Similarly, last month in Nevada Department of Human Resources vs. Hibbs (May 27, 2003), the Supreme Court, speaking through Chief Justice William H. Rehnquist, sustained the Family and Medical Leave Act of 1993 as a reasonable congressional measure to correct and to forestall unconstitutional gender stereotyping.

Massachusetts has chosen, unless their Constitution undergoes amendment, to undergo one of those grand expirements. Now, earlier I mentioned Bush. Of course, both parties have voices urging federal legislation; and Clinton signed the first attempt: the Protection of Marriage Act. Point here is point out one more instance where, I'm predicting, the great philosophies (federalism/potent state power) of some conservatives are about to take a back seat.