This article is from the archive of our partner National Journal

The tide is shifting for gay marriage across the country—even in the GOP.

Six Republican congressional challengers this year support same-sex marriage, along with four House incumbents and one Senate incumbent running for reelection—the most in history, according to the Freedom to Marry campaign. If they win, they'll join three current members of Congress not up for reelection who've publicly voiced support for the issue.

At least one of those challengers is trying to use a pro-gay-marriage position to her advantage. Monica Wehby, an Oregon Republican running for the Senate, released a TV ad Tuesday putting her support for same-sex marriage in the spotlight. The commercial features Ben West, one of the plaintiffs who successfully sued in Oregon federal court for the right to marry his now-husband, Paul Rummell.

"I'm a very independent-minded person, like our state," Wehby told Politico. "I've always felt government should stay out of it. This isn't a change in thought for me at all."

Just two years ago, only five Republicans who had a chance of winning ran for Congress and publicly backed gay marriage, according to the pro-marriage equality PAC American Unity, and only one Republican member of Congress publicly backed same-sex marriage: Rep. Ileana Ros-Lehtinen of Florida, whose transgender son is an LGBT rights advocate. Jeff Cook-McCormac, a senior adviser at pro-marriage-equality PAC American Unity, told National Journal that, including Ros-Lehtinen, eight current congressional Republicans have asserted their support: fellow House Floridian David Jolly; Reps. Charlie Dent and Richard Hanna of Pennsylvania and New York, respectively; and Sens. Susan Collins of Maine, Mark Kirk of Illinois, Rob Portman of Ohio, and Lisa Murkowski of Alaska.

The relatively rapid shift mirrors Americans' views. In 2012, half of Americans supported legalizing gay marriage; in May of this year, that number had climbed to 55 percent. As of March, 39 percent of all Republicans back gay marriage, with 61 percent of those 18 to 29 voicing their support.

"The political dynamics are changing," Cook-McCormac says. "The GOP faces a demographic reality, and candidates like Wehby show that the issue is "completely in line with their views on individual liberty and limited government."

Correction and update: An earlier version of this story miscounted the number of members of Congress who support same-sex marriage but are not running for reelection. There are three. This story has also been updated with candidates from 2012.

This article is from the archive of our partner National Journal.

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