WATCH: Ad Makes Republican Case for Marriage Equality

San Diego mayor Jerry Sanders, a Republican and marriage equality supporter, appears in an ad for the marriage cause that will air in the Tampa, Fla., market during next week's Republican National Convention.

"As a Republican, I believe in conservative values like responsibility and limited government," Sanders says in the ad, titled "Family and Freedom," a project of the Human Rights Campaign and Freedom to Marry. He makes a case for why Republicans should endorse marriage equality: "Marriage strengthens families, and we need more of that in this country, not less."

Sanders, the father of a lesbian daughter and a chair of Mayors for the Freedom to Marry, also points to prominent Republicans who support marriage equality, including Dick and Lynne Cheney, Laura Bush, Ted Olson, and Cindy McCain.

The party has taken a stand against marriage rights for gay couples in its platform, to be ratified at the convention. However, LGBT activists do not intend to give up the fight.

"While the GOP's official position on marriage equality is stale to most Americans, there is a growing movement within the party heading inexorably toward fairness," said HRC president Chad Griffin in a press release. "This ad is proof that we're not willing to leave any group of Americans behind in the national conversation over treating gay and lesbian couples with dignity and respect."

Watch the ad below.