The U.S. Democratic Party is ready to formally include same-sex marriage in its official campaign platform for the first time in its history.

An unnamed Democratic official says the party's platform drafting committee approved language endorsing homosexual marriages during a meeting Sunday in Minneapolis. The issue will be voted on in September during the Democratic National Convention in Charlotte, North Carolina, where President Barack Obama will be formally nominated as the party's candidate for re-election.

The party's position comes two months after Mr. Obama became the first U.S. president to openly support same-sex marriage.

Brian Brown, the president of the National Organization for Marriage, which opposes same-sex marriage, says his group intends to make the Democratic Party's position a defining issue in the November presidential election.