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Why Dem senators still opposing gay marriage might not change their minds soon

And then there were three.

On Monday, Sen. Tim Johnson, D-S.D., became the latest senator to announce his support of same-sex marriage.

"After lengthy consideration, my views have evolved sufficiently to support marriage equality legislation," he said in a statement. "This position doesn't require any religious denomination to alter any of its tenets; it simply forbids government from discrimination regarding who can marry whom." 

Johnson, who declined to run for re-election next year, joins Sens. Heidi Heitkamp, D-N.D., and Joe Donnelly, D-Ind., who on Friday declared their support for gay marriage.

With these new announcements, a total of 54 senators now support it -- 52 of them Democrats or Democratic-leaning independents and two of them Republicans. 

Only three Democratic senators now remain opposed: Sens. Joe Manchin, D-W. Va.; Mary Landrieu, D-La.; and Mark Pryor, D-Ark.

But three different aspects of home-state politics suggest that the remaining Dem senators might not be changing their position anytime soon – 1) the percentage of constituents who say that religion is important to them, 2) pending re-elections, and 3) Mitt Romney’s margin-of-victory in the state.

Residents of Arkansas and Louisiana are among the most committed to religion in the nation, according to a 2009 state-by-state analysis by the Pew Forum on Religion & Public Life. (The data represent the most current state-level information available.)

Seventy-four percent of Arkansas respondents and 73 percent of Louisiana respondents said religion is very important to them. That’s compared with just 56 percent -- the national average -- who said that in both Johnson’s South Dakota and Heitkamp’s North Dakota. Sixty percent of residents in Manchin’s West Virginia agreed that religion is very important to them, which is tied with the percentage who said that in Donnelly’s Indiana.

In addition, both Landrieu and Pryor are up for re-election next year (while Manchin doesn’t face re-election until 2018). And Romney easily won in West Virginia (getting more than 62 percent of the vote there), Louisiana (58 percent), and Arkansas (61 percent) in 2012.

So bottom line: The states where Democratic senators continue to oppose gay marriage -- by one measure or another -- are slightly more conservative than states where Democratic senators have recently changed course.

Joe Manchin (D-W. Va.)

  • % Who say religion is important: 60
  • Election year: 2018
  • Mitt Romney: 62%

Mary Landrieu (D-La.)

  • % Who say religion is important: 73
  • Election year: 2014
  • Mitt Romney: 57.8%

Mark Pryor (D-Ark.)

  • % Who say religion is important: 74
  • Election year: 2014
  • Mitt Romney: 60.5%