Wisconsin Rep. Tammy Baldwin has endorsed adding gay marriage to the 2012 Democratic platform.

“I think that would be tremendous, and we have to be focusing on advancing equality in so many different realms,” Baldwin told gay weekly The Washington Blade. “It's a statement of values, and I think it's very important to be included.”

Baldwin, 50, could become the first openly gay U.S. senator. Polling shows she is running close to her Republican rival, former Wisconsin Governor Tommy Thompson, who is considered the front-runner in the race for the seat being vacated by Wisconsin Senator Herb Kohl.

On Wednesday, Baldwin announced that her campaign had brought in more than $2 million in the first quarter of 2012 fundraising.

She joins a growing chorus of elected officials who have endorsed putting marriage equality in the platform, including Democratic National Convention chair Antonio Villaraigosa, House Minority Leader Nancy Pelosi, U.S. Senate candidate Elizabeth Warren and nearly two dozen U.S. senators.

Last month, Freedom to Marry launched its Democrats: Say I Do campaign with the goal of adding marriage equality to the Democratic platform.

“Rep. Baldwin … joins numerous party leaders and tens of thousands of Democrats who have signed our online petition in speaking up for the Democratic values of freedom, family and inclusion that are the core of the case of the freedom to marry,” said Evan Wolfson, founder and president of Freedom to Marry.

(Related: Obama is “moving in the right direction” on gay marriage, Tammy Baldwin says.)