Minnesota legislators determined to legalize same-sex marriage opened up the newest battle ground over the issue, unveiling a proposal that would allow gay and lesbian couples to wed.

"This is a day that Minnesotans should be very proud of," said Sen. Scott Dibble, a Minneapolis Democrat who is a chief sponsor of the bill. "Our challenge in coming weeks is that we really have this discussion with renewed energy, about why marriage matters, why family matters."

The new legislative push is the culmination of a 10 year fight over the issue, beginning with proposals to further restrict marriage solely to heterosexual unions. Sensing a national, tidal shift on the issue, advocates now believe this is the year Minnesota will join fewer than a dozen states that have legalized same-sex marriage.

The new proposal would allow gay and lesbian couples to marry, but ensures that religious leaders who are opposed are not forced to wed same-sex couples. Only faiths and religious groups that welcome same-sex unions could perform the ceremonies.

Opponents argued this is precisely why the state needed the constitutional amendment which voters defeated in November.

"It is exactly what we warned would happen," said John Helmberger, chairman for Minnesotans for Marriage, the lead group trying to block same-sex marriage. "And it is a huge mistake to believe the lie that the results of the November election was a mandate to legalize gay marriage."

They have argued that same-sex marriage would be taught in schools if it became legal. And they have said that children are best served by marriages between a man and a woman.

State Rep. Glenn Gruenhagen said that homosexuality was a choice and that they should not be rewarded with the same marital rights as hertosexual couples. "The concept you are born that way is an unscientific lie."

The issue has gripped the state most intensely for nearly two years, when the GOP-led Legislature put a measure on the ballot to constitutionally limit marriage to unions between a man and a woman. In November, voters rejected the measure and handed DFLers control of the legislature. Along with a DFL governor, the dramatic political shift has given same-sex marriage advocates their best shot yet at changing Minnesota law.

Passage remains far from certain, however. DFL legislative leaders said the budget fight remains their top priority and have not committed to bringing up the marriage issue for a floor vote.

In the last couple weeks, Republican Sen. Branden Petersen of Andover said he would support the measure, the first GOP member to do so. This week, Republican former State Auditor Pat Anderson said she supported Petersen and same-sex marriage.

Petersen had meetings in his district and could not attend the news conference, but issued a statement expressing his strong support.

"As a strong proponent of limited government, conservative principles and individual liberty, I am proud to add my name as co-author of legislation to secure the freedom to marry for same-sex couples in Minnesota," he said.

If same-sex marriage becomes law, the weddings could begin in August.