With deafening cheers ringing throughout the Capitol corridors, the Minnesota Senate approved a bill to legalize same-sex marriage Monday, May 13, positioning the state to become the 12th to put marriage equality into law.

It passed on a 37-30 vote, with one Republican crossing party lines to vote “yes” and three Democrats voting “no.”

Gov. Mark Dayton is expected to sign the bill Tuesday, and gay couples could begin marrying Aug. 1.

“Sometimes the simplest bills are the most powerful in affecting peoples’ lives for the better,” said bill sponsor Sen. Scott Dibble, a Minneapolis DFLer who previously married Richard Leyva in California.

“With just a few words, we have the ability to bring loving families across the entire state of Minnesota into the full sunshine of equality and freedom that they’ve been denied for so long.”

Gay marriage supporters far outnumbered opponents Monday at the Capitol. Decked in orange and blue, they chanted, “We’ve got your back,” as lawmakers left the Senate chamber.

St. Paul already has planned a celebration for Tuesday, with Dayton’s 5 p.m. bill signing on the Capitol steps and a “Love is Law” outdoor concert afterward at Ecolab Plaza downtown.

As word spread of the Senate vote tally, the rotunda thundered with cheers and applause. Among those celebrating was Mary Hartmann, 65, of St. Paul, who was in the center of it all with members of her synagogue.

“My partner and I have been together for 25 years,” Hartmann said. “We raised three children and have two grandchildren.

“And now,” she said with a smile, “we can stop living in sin.”

Opponents with their signature pink “Vote No” signs dotted the crowd of supporters or gathered in small prayer groups.

They said that along with the celebration, there will be grieving, too. Sen. Dan Hall, R-Burnsville, said legalizing same-sex marriage would divide the state like nothing since the Civil War, destroying businesses and confusing children.

“People ask me, ‘Senator Hall, don’t you want to be on the right side of history?’ The truth is, I’m more concerned about being on the right side of eternity,” Hall said.

The bill changes state law to specify that marriage is a civil contract between “two persons” rather than “a man and a woman.”

It offers protection for clergy and religious organizations that don’t want to solemnize gay marriages that supporters argue is the strongest such language in the nation.

Opponents of same-sex marriage argued that those religious protections don’t go far enough. They argue that businesses, public officials and nonprofit groups that disagree won’t be able to refuse services if they have religious objections to gay marriage.

That would mean, for example, marriage counselors or wedding photographers would have to take on clients, regardless of their own religious viewpoints, said Sen. Paul Gazelka, R-Nisswa.

But senators rejected his amendment that would have protected faith-based entities and private individuals, not just those affiliated with churches.

Same-sex marriage supporters argued that it’s already illegal under the state’s Human Rights Act for a business to refuse service based on religious objections. Legalizing gay marriage wouldn’t change that.

Sen. Ron Latz, DFL-St. Louis Park, said Gazelka’s amendment would have gutted the state’s Human Rights Act passed by lawmakers 20 years ago and legitimize discrimination against people for who they marry.

That would include interracial couples, a Lutheran who marries a Catholic or someone with a disability who weds someone without a disability. Latz said he strongly believes legalizing gay marriage is the civil rights issue of this generation.

“God made gays. And God made gays capable of loving other people,” Latz said.

Sen. Jeff Hayden, DFL-Minneapolis, talked to his colleagues about his marriage and why they should vote yes. He is black, and his wife, Terri, is white. There was a time their interracial marriage would have been illegal in some states. He said his two children know many same-sex couples well and are better people because of it.

“It’s going to be OK. Everything is going to be fine in Minnesota,” Hayden told opponents of gay marriage.

Opponents argued that when voters in the fall rejected a constitutional amendment to limit marriage to heterosexuals in Minnesota, critics of the proposal said nothing would change. Same-sex marriage still would be illegal.

“Do they feel betrayed today? Absolutely. Do they feel lied to? Yeah,” said Sen. Mary Kiffmeyer, R-Big Lake.

Lilian Romero, 34, of St. Anthony, who came to the Capitol with her church group, said she questioned both homosexuality and gay marriage because she’s been told of some gay men and lesbians who underwent therapy to become straight.

Romero also said same-sex marriage conflicts with her religious beliefs.

“We believe in what God created — man and woman,” said Romero. “This is a spiritual problem.”

Several lawmakers were conflicted in the days leading up to Monday’s vote. One suburban Republican said publicly he would vote for the bill, and three DFLers from outstate Minnesota pledged to vote “no.” They kept those promises.

Sen. Lyle Koenen, DFL-Clara City, said he voted against the bill because it was clear it was something his constituents wanted him to do. About 63 percent of voters in his western Minnesota district voted last fall for the proposed constitutional amendment.

“I decided that I should do the best job at representing my district,” Koenen said. “I’m comfortable with that. I know where they’re coming from.”

DFL Sens. LeRoy Stumpf of Plummer and Dan Sparks of Austin also voted “no.”

Sen. David Senjem, R-Rochester, said he was torn until the vote was taken but ultimately voted “no.”

Senjem’s district was almost split on the amendment, with a slim majority voting against it. He said it was the hardest vote he ever had to take.

“You struggle with your own values and beliefs, as well as changing sentiments of society. Look at my desk,” Senjem said, nodding to hundreds of notes sent to him on the Senate floor. “I have a lot of neighbors out there, a lot of friends who I have a lot of respect for and don’t want to hurt.”

Sen. Branden Petersen of Andover, the sole Republican to vote for the bill, said that after months of internal debate, he decided he had to support marriage equality.

Otherwise, he said, he couldn’t honestly look in the mirror and tell himself he was doing what he thought was right.

Petersen thanked his wife, Jessica, for being with him throughout the debate. And he had some words of advice to his two children, who are just 1 and 2 years old, whether they agree with his decision or not someday.

“In all things related to your faith, to your freedom, to your family, be bold, be courageous,” Petersen said, “and you’ll never regret a day in your life.”

Christopher Snowbeck contributed to this report. Megan Boldt can be reached at 651-228-5495. Follow her at twitter.com/meganboldt.

ST. PAUL THROWS A PARTY

— Gov. Mark Dayton will sign “Freedom to Marry Bill” into law at 5 p.m. Tuesday on the south steps of the state Capitol.

— After the Capitol ceremony, Minnesota Freedom Band will lead a procession to a party at Ecolab Plaza, 375 N. Wabash St.

— From 6 to 10:15 p.m., the “Love is Law” celebration will be held at Ecolab Plaza, There will be food, bands and beverages.