ABC News’ Teddy Davis reports: Gay rights are once again being hotly debated in the state of Vermont. Back in 2000, in response to a decision of the state’s Supreme Court, Vermont became the first state in the nation to enact a civil unions law. In the years since then, California, New Jersey and New Hampshire have followed suit in providing state benefits to same-sex couples outside of the institution of marriage either through domestic partnership laws or Vermont-style civil unions. Massachusetts and Connecticut have gone a step further: Both states have adopted same-sex marriage via court decision. No state has adopted same-sex marriage through the approval of the legislature and governor. On multiple occasions, same-sex marriage has passed California’s Democratic-controlled legislature before being vetoed by Republican Gov. Arnold Schwarzenegger. Vermont legislators who were hoping to become the first state to approve same-sex marriage through non-judicial means were dealt a blow on Wednesday by the state’s governor. Speaking at a news conference, Vermont Republican Gov. Jim Douglas said he will veto same-sex marriage if it continues to advance in the state legislature and reaches his desk. Douglas explained his stance by saying that he thought Vermont’s first-in-the-nation civil unions law provided adequate legal protection to same-sex couples. "For those reasons and because I believe that by removing any uncertainty about my position we can move more quickly beyond this debate, I am announcing that I intend to veto this legislation when it reaches my desk," said Douglas. The gubernatorial announcement was swiftly rebuked by supporters of same-sex marriage. "History will judge Jim Douglas on the wrong side of this issue," said Vermont House Speaker Shap Smith (D). One prominent Vermont Democrat who is still standing by the state’s civil unions law is former presidential candidate Howard Dean. Dean is the former Vermont governor who approved a civil unions law nine years ago in response to the state Supreme Court’s decision in Baker v. State. During a March 2 interview with ABCNews.com, Dean said "if a state wants to do marriage that is their business, I have no problem with that." But while he has no objections to a state enacting same-sex marriage, he does not actively support it and he defended civil unions as an equal institution under Vermont state law. "From a legal point of view, civil unions in Vermont are equivalent to marriage for same-sex couples," said Dean. "So what we are really arguing about is a particular word." Asked about last year’s Connecticut Supreme Court decision which struck down civil unions as violating that state’s constitutional guarantees of equal protection under the law, Dean said, "I don’t agree with the gay community that all civil unions are unequal and there’s some disagreement inside the gay community on whether or not we should have marriage." "But you know," he continued, "why are we having this discussion. I mean, you know the movement is going forward for equal rights and I support that movement, however it ends up coming out." ABC News’ Ferdous Al-Faruque contributed to this report.