The Wall Street Journal's Washington Wire blog:

Bob Vander Plaats, an influential Iowa conservative who unveiled his anti-gay-marriage pledge last week, may have gone too far.

Former Massachusetts Gov. Mitt Romney outright rejected the “Marriage Vow” written by Mr. Vander Plaats and his advocacy group, The Family Leader.

... “Mitt Romney strongly supports traditional marriage,” Mr. Romney’s spokeswoman Andrea Saul, said in an email. “But he felt this pledge contained references and provisions that were undignified and inappropriate for a presidential campaign.”

... A spokesman for former House Speaker Newt Gingrich, a vocal opponent of gay marriage, said the pledge had a long list of problems and declined to sign it unless it was changed.

ABC News The Note blog:

On the campaign trail in Iowa today, Tim Pawlenty announced his decision not to sign the pledge, and instead released a video discussing his personal faith.

"Voters have a right to know about their leaders' faith and values, and how those beliefs may shape their decisions. To that end, today my campaign released a new video in which both Mary and I speak directly and openly about our faith," Pawlenty said in a statement. "I fully support traditional marriage. Unequivocally. The traditional family faces enormous challenges in America, and if elected I would vigorously oppose any effort to redefine marriage as anything other than between one man and one woman."

Jon Huntsman has said he does not plan to sign any pledges while seeking the Republican presidential nomination.