MINNEAPOLIS (AP) — A campaign to defeat a constitutional gay marriage ban on November’s ballot released its first TV commercial Tuesday, featuring a GOP-supporting, Catholic married couple whose friendship with their lesbian neighbors convinced them to vote against the amendment.

The ad from Minnesotans United for All Families, a coalition of gay rights groups, was posted online early Tuesday and would make a TV debut later in the day in the Twin Cities and Duluth. Spokeswoman Kate Brickman said the ad, which would eventually be broadcast statewide, was the first salvo in a multimillion dollar campaign to air the “vote no” ad continually until the election.

“We decided that once we go up, we want to stay up,” Brickman said.

The principal campaign in support of the amendment, Minnesota for Marriage, will start broadcasting its TV ads Oct. 1.

The Minnesotans United for All Families ad features John and Kim Canny of Savage, a Minneapolis suburb. It identifies them as Catholics and Republicans, who have been married for 13 years and who have three children.

“Marriage is really important to me. I didn’t really think a lot about same sex marriage,” John Carny says. Kim Carny says a lesbian couple who live in their neighborhood with their adopted son “taught all of us in our little suburban world.”

The amendment, if passed, would harden an existing gay marriage ban under state law by adding it to the constitution. If it is defeated, gay marriage would still be illegal under state law.

Minnesota for Marriage was planning a Tuesday event at the Minnesota Capitol featuring religious leaders from around the state talking about why they think it’s important to pass the amendment.