"People, as a rule, like strong opinions; “We are in favor of civil unions but opposed to gay marriage” might work for the moment, but in the absence of a unifying force like Bush, such nebulous half-slogans will fall on deaf ears.
The problem is that their real opinion is this: "We are in favor of gay marriage, but we don't think we will win if we say that."
But since all the voters know this anyway, their equivocation is of little use.
You're right of course. Clearly they support gay marriage, they just don't want to admit it. And they don't have to because they know the Courts will eventually do for them what the people/legislatures would (or already have) reject. Then they hope that the people will convey to a SCOTUS decision a certain amount of respect and awe that they unfortunately have to Roe v Wade. Then they need only stall and have their media allies do story after story celebrating gay marriages, all in the hopes that it will sway public opinion enough to make any attempt to overturn or defy SCOTUS a long shot at best.
Still, even if we go along with their stated position, I have yet to see any prominent Democrat be asked whether or not they support the judicial imposition of civil unions.
And that is key, because many states, probably most states, would reject any legal recognition of same-sex unions no matter what euphemism for marriage is used.