Marriage is a union between a man and a woman recognized by religious institutions. As such, it is a religous term and not subject to legislation under the 1st Amendment of the Constitution. Historically, there was no reason to differentiate it from civil unions, which are special, familial unions recognized by the government (hence the term "civil".) When you have to supply an adjective to further describe a noun, that means that you are describing something different than the noun's original definition. Which of course means that same-sex marriage or gay marriage, is most definitely NOT the same thing as marriage.