The following wikipedia entry describes Lieberman's opposition to a Constitutional amendment banning gay marriage. Gay rights In 2004, Lieberman scored a rating of 88 out of 100 by the Human Rights Campaign (HRC), one of the largest civil rights organization working to achieve gay, lesbian, bisexual and transgender equality."[44] Lieberman voted no on a constitutional ban of same-sex marriage.[44] In 2003, in response to the Massachusetts ruling that sanctions gay marriage, Lieberman stated, "although I am opposed to gay marriage, I have also long believed that states have the right to adopt for themselves laws that allow same-sex unions," and "I will oppose any attempts by the right wing to change the Constitution in response to today's Massachusetts Supreme Court ruling, which would be unnecessary and divisive."[45] To be sure, this doesn't mean he's in favor of having states recognize gay unions. In a 2004 press release, Lieberman attributes his opposition more to his philosophy on Constitutional amendments than on gay rights: I believe that marriage is a legal status that should be granted to the union of one man and one woman. I believe that because the marriage of a man and a woman is the best way to sustain the human race through the procreation and rearing of children. And therefore it is in the interest of our society to attach special benefits to the relationship of a man and woman joined together in marriage. That’s why I voted for DOMA, the Defense of Marriage Act, in 1996, and why I still support that law today. DOMA makes absolutely clear that marriage under federal law is a status that should be attainable only by one man and one woman, and that any State’s decision to define marriage otherwise has no effect on the definition of marriage under either federal law or the laws of other States. In other words, we already have a federal law on the books that precludes any couple other than an opposite sex one from claiming federal marriage benefits and that prevents one State from seeking to impose its view of marriage on its sister States. A constitutional amendment to that effect is therefore unnecessary at this time. But that still leaves him opposed to the Constitutional amendment.
Senator Lieberman Press Release..
“I oppose to the Federal Marriage Amendment because I believe that this effort to amend the Constitution to ban gay marriage is premature and therefore unnecessarily divisive,” Lieberman said.