Opponents of gay marriage in Maine are preparing to submit a referendum that would yank back the right of gay men and lesbians to marry in the state – even before the legislation has become law.

A gay marriage bill in the Augusta Statehouse would make the Pine Tree State the fifth to legalize gay unions. The state Senate approved the measure with a 21 to 14 vote on Thursday. Members of the House and Maine Governor John Baldacci, a Democrat, must also approve the bill for it to become law. (Baldacci has recently dropped his opposition to gay marriage, but has not said whether he would veto the law should it reach his desk.)

Gay marriage foes have already committed to its repeal. Mike Heath, head of the Maine Family Policy Council, announced the effort in an email Friday.

“Maine's Legislature will eliminate civil marriage by the end of May. We have started a People's Veto,” the group's website says. “Maine people twice rejected 'gay' rights in the past decade. Homosexuality is very sad, and sinful. Maine must not create a culture that winks at something so debilitating on so many levels. To present this 'orientation' as benign to impressionable children is the height of arrogance, and surely qualifies as evil.”

Under Maine law, voters can challenge a bill with a people's veto. To place a measure on the ballot this November requires opponents turn in 55,087 valid signatures by September 3 or 4 (at least 60 days before Election Day). Gathering of the signatures cannot begin until after the Legislature has adjourned, around July 17.

Heath is credited with two successful efforts to overturn gay rights initiatives in Maine, in 1998 and 2001.

The Christian conservative made news last September when he blamed the nation's financial crisis on gay unions. Writing at his blog (mikeheath.blogspot.com), Heath said amending state constitutions to ban gay marriage, and eliminating domestic partnerships and civil unions for gay and lesbian couples would make God “crack a smile.”

Opponents to the bill are likely to face stiff resistance in Maine. Three New England states – Connecticut, Massachusetts and Vermont – have already legalized gay marriage. New Hampshire appears likely to follow suit. Polling indicates that opposition to gay rights has subsided considerably in all six states.