Oxford English Dictionary Redefining Marriage
If Congress doesn't want to redefine marriage, the Oxford English Dictionary will just do it themselves. After all, that's their job.
Now that gay marriage has been legalized in the home of the world's most renowned dictionary, the OED is saying that they will monitor how usage of the word "marriage" changes. In other words, they are going to redefine marriage so that gay marriage is part of the definition.
Although changing the definition won't have any legal ramifications, the OED is considered a historical record of the English language, reflecting the changing of the times, and making their definition the authority on the word.