BOSTON (AP) – Gay marriage foes have filed a petition that would put a ban on both same-sex marriage and civil unions on the 2008 ballot.

The petition was filed by the Rev. Michael Carl, a minister at the Greenwood Union Church in Wakefield. Carl said he’s concerned lawmakers either won’t act or will forward a proposed constitutional amendment allowing civil unions to voters for the 2006 ballot.

If that happens, he said he will move forward with the petition, which he filed Feb. 27 with state Attorney General Thomas Reilly’s office.

“In the event the Legislature either fails to act or passes a proposed amendment that includes civil unions, that is incrementalism, and I just can’t agree with that,” Carl said.

“We’re talking about the benchmark foundational institution of all civilization since time immemorial,” he said.

On March 29, lawmakers are scheduled to reconvene a special legislative session aimed at getting an amendment on the 2006 ballot.

That amendment defines marriage as the union of a man and woman and establishes civil unions in the state.

Carl’s proposal would amend the state constitution to read, in part: “Marriage … shall henceforth be defined in the Commonwealth as the voluntary, consensual union between one man and one woman.”

All statutes and laws of the Commonwealth of Massachusetts shall henceforth conform thereto.”

After the attorney general office’s approves the language on the petition, Carl and his supporters must collect signatures from 65,825 certified voters from at least four towns. Once those signatures are certified, a Constitutional Convention must consider it.

A citizen petition requires approval by one-quarter of the legislators – 51 votes – in the special combined session. If the measure clears that bar in the 2005-2006 session, and again in the 2007-2008 session, the amendment will be put before the voters in 2008.

Arline Isaacson, co-chairwoman of the Massachusetts Gay and Lesbian Political Caucus, said the petition was a “fallback” for gay marriage opponents in case things don’t go their way in the Legislature.

“Obviously, we would hate to see an initiative petition for a constitutional amendment to take our marriage rights away move forward,” she said.

Carl, a native of Texas and Massachusetts resident for three years, heads the Heritage Alliance, a political action committee he recently formed to field candidates to run against legislators who support gay marriage.

AP-ES-03-20-04 1220EST