Louis Marinelli, a former strategist for the anti-gay marriage group National Organization for Marriage (NOM), has announced a 21 city bus tour in support of gay marriage.

Marinelli quit the nation's most vociferous opponent of gay marriage last month, taking with him the group's official Facebook page and its 219,000 fans.

He's said that he had a change of heart while on board NOM's Summer for Marriage Tour 2010, a nationwide bus tour to rally opposition to gay marriage.

“Over the course of 30 days, we traveled more than 10,000 miles to spread a discriminatory message I once believed in to oppose same-sex marriage,” Marinelli wrote. “Ironically, it was that very summer tour that led me to change my mind and come to support marriage equality.”

The tour kicks off with an August 14 rally in San Diego and ends on the other side of the nation, in Augusta, Maine on September 7.

Marinelli, who remains a conservative, said the tour will reach out to conservatives, urging them to support marriage equality.

“Too many see support for gay rights as strictly a liberal issue,” he said. “That's a mistake. Supporting the constitutional rights of all citizens is a conservative issue, too.”

“The tour will seek to demonstrate to conservative legislators across the country that more and more people are coming to support marriage equality. If I, an opinionated conservative, can change my mind, it won’t be long before many other conservatives do, too. Not to mention independents,” he added.

In Iowa at least, Marinelli will have some competition in former Senator Jeff Angelo, who is expected on Wednesday to launch a new group for Republicans who support giving gay and lesbian couples the right to marry.