The 7 Senate Democratic Holdouts on Gay Marriage

With the decision Tuesday by Sen. Tom Carper of Delaware to endorse gay marriage, only seven Democratic senators are left who have not publicly announced their support, and there's good political reason behind their reticence. 

With Carper flip-flopping, nearly all of the Democrats who oppose gay marriage are from Republican states, with the exception of Florida’s Bill Nelson. Two are up for reelection in 2014, and are unlikely to change their mind before then.

Here’s a look at where all of them stand.

(AP Photo/Alex Brandon)

Mark Pryor of Arkansas

Why he will flip: He could feel pressure from his own party, especially as his colleagues are quickly flipping on the issue. Will Pryor want to be the last Democrat standing against gay marriage?

Why he won't flip: Pryor is up for reelection in deeply conservative Arkansas, which went for Mitt Romney over Barack Obama by 23 points in 2012. Pryor is socially conservative and has said through a spokesman that he has a moral belief that marriage should be between a man and a woman. Plus, Arkansas is one of 11 states that voted to ban gay marriage. It would be politically risky for Pryor to tack to the left ahead of the election.

(AP Photo/Alan Diaz)

Bill Nelson of Florida

Why he will flip: Florida voters are split on the issue, but a majority said gay marriage should be legal. According to a Washington Post poll from October, 54 percent of the state’s voters favored legalizing gay marriage. Still a perennial battleground, Florida has voted for Obama in each of the past two presidential elections. Nelson won’t be able to hold out against the tide of public opinion much longer.

Why he won't flip: In a recent interview, Nelson said he personally believes marriage should be between a man and a woman. Despite Florida’s battleground status, the Panhandle’s voters are much more similar to those in the Deep South on social issues. Being one of the last Democrats to change his mind would make it seem more politically craven, rather than out of principle.

(AP Photo/Michael Conroy)

Joe Donnelly of Indiana

Why he will flip: Already two Midwestern Republican colleagues—Rob Portman of Ohio and Mark Kirk of Illinois—have declared support for gay marriage. Plus, he endorsed expanding marriage benefits to gay couples, but stopped just short of endorsing gay marriage. He’s not up for reelection until 2018.

Why he won't flip: Donnelly is Catholic (he graduated from Notre Dame with a bachelor's and again with a law degree), and may not want to alienate the more traditional voters that made up much of his old House district, based in South Bend.  

(AP Photo/J. Scott Applewhite)

Mary Landrieu of Louisiana

Why she will flip: She's hinted that she personally backs gay marriage. In a statement issued last week, Landrieu said, "While my personal views have evolved, I will support the outcome of Louisiana's recent vote."

Why she won't flip: Like Pryor, Landrieu is one of five Democrats facing reelection in a state Mitt Romney carried. Louisiana is a conservative state that voted for the Republican candidate in the last four presidential elections. An overwhelming 78 percent of Louisiana voters also backed a referendum that defined marriage as between a man and a woman in 2004. Landrieu said she would respect the will of the voters, according to The Times-Picayune.

(Chet Susslin)

Heidi Heitkamp of North Dakota

Why she will flip: She won't have to face voters again until 2018, when gay marriage could be a less contentious issue. North Dakota is more libertarian-minded than socially conservative, recently rated as freest state in the nation by the libertarian Mercatus Center. 

Why she won't flip: Heitkamp spokeswoman Whitney Phillips reiterated that the senator believes gay marriage is a state issue, conveniently sidestepping the question. North Dakota approved a ban on gay marriage in 2004 and only 1.7 percent of North Dakotans identify themselves as lesbian, gay, bisexual, or transgender, the lowest percentage in the country, according to a recent Gallup Poll. 

(AP Photo/Haraz N. Ghanbari)

Tim Johnson of South Dakota

Why he will flip: Johnson is retiring after 17 years in the Senate, so he doesn't have to worry about any political consequences.

Why he won't flip: Johnson's son, U.S. attorney Brendan Johnson, is a potential Senate candidate in South Dakota, and the senator might not want to take a position that could harm his son politically. The elder Johnson’s office confirms that he believes marriage should be between a man and a woman.

(AP Photo/David Karp)

Joe Manchin of West Virginia

Why he will flip: His retiring colleague Jay Rockefeller, D-W.Va., backed gay marriage, and like Heitkamp, Manchin won't have to face voters again until 2018. In 2009, the Democrat-controlled lower chamber of the Legislature defeated a measure that defined marriage as between a man and a woman.

Why he won't flip: Still, West Virginia is a red state that Obama lost by 26 points in 2012, and Manchin has a conservative track record on social issues, backing the Defense of Marriage Act and voting against a bill that included repeal of Don't Ask Don't Tell.

CORRECTION: An earlier version of this article misidentified the pollster who surveyed voters in North Dakota. It was a Gallup Poll.