The pressure is being put on President Barack Obama to evolve on his stance of supporting gay marriage as four former Democratic National Committee chairs made a public statement today calling for marriage equality to be included in the party's 2012 platform.

The former DNC chairs are Howard Dean, Donald Fowler, Steve Grossman and David Wilhelm. They are joining Freedom to Marry's campaign, "Democrats, Say I Do."

The Democratic National Convention takes place Sept. 3 in Charlotte, N.C., where the state is currently undergoing a war to fight off a ban on gay marriage.

The former DNC chairs issued the following statement, according to a press release from Freedom to Marry:

We are proud that the Democratic Party fights for working families, economic justice, and equal opportunity for all. Times change but our principles must always remain strong. That is why, as former chairs of the Democratic National Committee, we stand with Freedom to Marry, 22 Democratic senators, Leader Nancy Pelosi, and more than 35,000 Americans in urging the Party to include a freedom to marry plank in the platform that is ratified at the Democratic National Convention in Charlotte this September.

Evan Wolfson, founder and president of Freedom to Marry, praised the former DNC chairs' decision to vocally support same-sex marriage as part of the Democratic party's official platform.

"Fighting for families, freedom, and inclusion in the American Dream is the Democratic Party’s DNA — its history, values, and vision for the country. That's why so many of the most influential Party leaders — including, today four of the most recent Party chairs — support a freedom to marry plank in the Democratic Party platform," Wolfson said. "

"Freedom to Marry welcomes their names alongside the tens of thousands of Americans who have signed our ‘Democrats Say I Do’ online petition for a platform plank, part of the growing majority for marriage nationwide speaking up for the freedom to marry," he added.

The proposed plank from Freedom to Marry states:

The Democratic Party supports the full inclusion of all families in the life of our nation, with equal respect, responsibility, and protection under the law, including the freedom to marry. Government has no business putting barriers in the path of people seeking to care for their family members, particularly in challenging economic times. We support the Respect for Marriage Act and the overturning of the federal so-called "Defense of Marriage Act," and oppose discriminatory constitutional amendments and other attempts to deny the freedom to marry to loving and committed same-sex couples.

Photo: Howard Dean is one of four former DNC Committee chairs urging the Democratic party to include support for gay marriage in its 2012 platform.