The Washington Post has this item examining how the issue of same-sex marriage might impact U.S. Senate races.
Combined data from Washington Post-ABC News polls do show that while the country as a whole tilts in favor of gay marriage, voters in some key swing states oppose it.
Seven of the 11 Democratic nominees or likely nominees running for open seats this cycle already support gay marriage. Of those, four are running in swing states — Rep. Tammy Baldwin in Wisconsin, Rep. Shelley Berkley in Nevada, Rep. Martin Heinrich in New Mexico, and former Sen.Bob Kerrey in Nebraska. (Rep. Mazie