Former Georgia Congressman Bob Barr will be the keynote speaker at a fundraiser for gay GOP group Log Cabin Republicans.

Barr, a Republican turned Libertarian, authored the Defense of Marriage Act (DOMA), the 1996 bill that bans federal agencies from recognizing the marriages of gay and lesbian couples.

In 2009, Barr came out against the law he authored.

“It truly is time to get the federal government out of the marriage business,” Barr wrote in an op-ed published in the Los Angeles Times.

Barr argued that DOMA had run afoul of the federalist principle of states' right to self determination because it only protects those states that don't want to accept the marriages recognized by another state. It is “one-way federalism,” Barr wrote.

Furthermore, Barr argued, the law punishes those states that do choose to grant marriages or civil unions to gay couples by invalidating those unions on the federal level.

“[T]he heterosexual definition of marriage for purposes of federal laws – including, immigration, Social Security survivor rights and veteran's benefits – has become a de facto club used to limit, if not thwart, the ability of a state to choose to recognize same-sex unions.”

Barr is expected to address the Log Cabin Republicans at their annual 2011 national dinner, which will take place at the Hilton Anatole Hotel in Dallas, Texas on April 30.

Former Republican National Committee Chairman Ken Mehlman, who came out gay last year, is also expected to attend the event.