Teri McClain, left, and Mary Beth Brotski stand with signs supporting President Obama in Seattle. (Elaine Thompson/AP)

The news was first reported by the Washington Blade.

President Obama came out in support of gay marriage in May, but making it a part of the Democrats’ official party platform represents another major step for the same-sex marriage movement, even beyond the president’s endorsement.

The platform drafting committee met in Minneapolis over the weekend. The full platform committee will meet in Detroit two weeks from now to take the next step, and then the platform will receive an up-or-down vote at the Democratic National Convention in Charlotte early in September.

It’s not yet clear exactly what gay marriage language is included in the party platform, and Democrats declined to comment Monday. The party could offer a broad endorsement for gay marriage without going into specifics, or it could endorse a federal law.

Regardless, gay marriage advocates hailed the decision Monday.

“This is a historic move by the Democratic Party that places it squarely on the right side of history, alongside President Obama,” said Rick Jacobs, founder of the Courage Campaign. “For the first time, a major U.S. political party has embraced gay and lesbian people as full Americans.”

But while Obama and many Democrats have endorsed gay marriage, not everyone in the party is on board — including many big-name Democratic Senate candidates running in swing states.

Republicans and conservatives signaled immediately that they would make an issue of the Democrats’ gay marriage stance in those states.

“If the DNC gets its way, the marriage amendments adopted in Ohio, Virginia, Florida, Colorado, Nevada and elsewhere will be overturned,” said National Organization for Marriage president Brian Brown. “That makes the definition of marriage a key issue in these swing states, and we fully intend to make sure that people realize that the outcome of the election is a proxy for the survival of traditional marriage in our nation.”