I came across a very interesting look at how his views on the subject of 'gay marriage' have changed since 1996, when he was running for the Illinois State Senate for the 13th district. At that time he was quite clear that he supported 'gay marriage'. By 2004, however, when his transformation from a State to a national politician was beginning he had modified (see also here) his public views to say that he did not support 'full marriage' for gays, but instead supported 'civil unions', and his reasons for changing his views were quite clearly stated in terms of naked political strategy:
Q: Do you have a position on marriage vs. civil unions?
I am a fierce supporter of domestic- partnership and civil-union laws. I am not a supporter of gay marriage as it has been thrown about, primarily just as a strategic issue.
I think that marriage, in the minds of a lot of voters, has a religious connotation. I know that's true in the African-American community, for example. And if you asked people, ‘should gay and lesbian people have the same rights to transfer property, and visit hospitals, and et cetera,' they would say, ‘absolutely.' And then if you talk about, ‘should they get married?', then suddenly ...
He was pinned down with further questions, eliciting these further remarks:
Q: There are more than 1,000 federal benefits that come with marriage. Looking back in the 1960s and inter-racial marriage, the polls showed people against that as well.
Since I'm a product of an interracial marriage, I'm very keenly aware of ...
Q: But you think, strategically, gay marriage isn't going to happen so you won't support it at this time?
What I'm saying is that strategically, I think we can get civil unions passed. I think we can get SB 101 passed. I think that to the extent that we can get the rights, I'm less concerned about the name. And I think that is my No. 1 priority, is an environment in which the Republicans are going to use a particular language that has all sorts of connotations in the broader culture as a wedge issue, to prevent us moving forward, in securing those rights, then I don't want to play their game.
If Massachusetts gets marriage and this gives momentum to the proposed federal Constitutional amendment against gay marriage?
I would oppose that.
According to Windy City Times he called later to clarify he was opposed to a constitutional amendment banning gay marriage and that he proposed the two State bills (in 2004) banning same-sex marriage. WCT states that he has remained consistent with this 2004 view during his Presidential campaign. WCT concludes its report by writing: "A rose is a rose is a rose, but civil unions are not “marriage” unless 100 percent of the benefits are the same across all states and the federal government."
It will be instructive to see what he does now that he has the power and prestige of Presidential authority to back his views, even if such power is in practice limited by what he can get through Congress.