"The research that I did uncovered that a civil union didn't equal a civil marriage."
His statement is undeniable as a description of the current political landscape: many opponents of same sex marriage do not object to civil unions for same-sex couples, and many advocates of gay marriage are not satisfied with civil unions.
Yet Baldacci's statement is also puzzling: for all practical purposes, civil union and civil marriage are identical.
So how might governments resolve the conflict? By exiting the "marriage" business and providing civil unions only to both same-sex and opposite-sex couples.
This accomplishes any legitimate goal of having government define and enforce the particular bundle of contracts (regarding inheritance, property, children) known as civil marriage. But it leaves the controversial aspect of this action - using the term marriage - to private parties.
Under this policy, some couples will just get civil unions. Some couples will also get "married" in religious ceremonies, but these will have no legal significance. This will apply to both same-sex and opposite-sex couples.
Everybody should be happy with this arrangement. Right?