Seven senators who have embraced same-sex marriage in 2013

Sen. Kay HaganKay Hagan Former Sen. Kay Hagan in ICU after being rushed to hospital GOP senator floats retiring over gridlock 2016’s battle for the Senate: A shifting map MORE (D-N.C.) on Wednesday became the seventh senator and sixth Senate Democrat to announce her support for same-sex marriage this year.

The other senators who have shifted their positions in the last month are Rob PortmanRob PortmanGOP governors defend Medicaid expansion Senators introduce dueling miners bills Schumer puts GOP on notice over ObamaCare repeal MORE (R-Ohio), Mark BegichMark BegichThe future of the Arctic 2016’s battle for the Senate: A shifting map Trump campaign left out of Alaska voter guide MORE (D-Alaska), Claire McCaskillClaire McCaskillFive things to watch for in Mnuchin hearing Senators introduce dueling miners bills GOP must avoid Dems' mistakes when replacing ObamaCare MORE (D-Mo.), Mark WarnerMark WarnerOvernight Cybersecurity: Dems split on Manning decision | Assange looking to make deal The Hill's 12:30 Report Manning commutation sparks Democratic criticism MORE (D-Va.), Jay RockefellerJay RockefellerObama to preserve torture report in presidential papers Lobbying world Overnight Tech: Senators place holds on FCC commissioner MORE (D-W.Va.) and Jon TesterJon TesterSenators introduce dueling miners bills Live coverage: The Senate's 'vote-a-rama' Dems attack Trump SEC pick's ties to Wall Street MORE (D-Mont.). Portman is the only Republican senator to back gay marriage.

Only nine Senate Democrats have not publicly embraced same-sex marriage, according to a report by Time magazine. 

Sens. Mark PryorMark PryorCotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm Top Democrats are no advocates for DC statehood MORE (Ark.), Tom CarperTom CarperPruitt says his EPA will work with the states Dems prepare to face off with Trump's pick to lead EPA Justice, FBI to be investigated over Clinton probes MORE (Del.), Bob CaseyBob CaseyLive coverage: Senators grill Trump's Treasury pick Live coverage: Tom Price's confirmation hearing Senate Democrats brace for Trump era MORE Jr. (Pa.), Joe DonnellyJoe DonnellySenators introduce dueling miners bills Government to begin calling Indiana residents Hoosiers Pence meets with Kaine, Manchin amid Capitol Hill visit MORE (Ind.), Tim JohnsonTim JohnsonCourt ruling could be game changer for Dems in Nevada Bank lobbyists counting down to Shelby’s exit Former GOP senator endorses Clinton after Orlando shooting MORE (S.D.), Heidi HeitkampHeidi HeitkampSenate Democrats brace for Trump era Senators introduce dueling miners bills A small business executive order: Justification for regulation MORE (N.D.), Mary LandrieuMary LandrieuFive unanswered questions after Trump's upset victory Pavlich: O’Keefe a true journalist Trump’s implosion could cost GOP in Louisiana Senate race MORE (La.), Joe ManchinJoe ManchinOvernight Cybersecurity: Dems split on Manning decision | Assange looking to make deal What we learned from Rick Perry's confirmation hearing Manning commutation sparks Democratic criticism MORE (W.Va.) and Bill NelsonBill NelsonLive coverage: Senators grill Trump's Treasury pick Trump's Commerce pick admits to unknowingly hiring undocumented worker Senate Democrats brace for Trump era MORE (Fla.) are the Democratic senators who have not backed gay marriage.

Polls show a majority of voters now support gay marriage, and Democratic politicians in particular have raced to side themselves with public opinion. 

President Obama announced his support for gay marriage last year, and earlier this month former Secretary of State Hillary ClintonHillary Rodham ClintonBill Clinton accusers snap picture at Trump gala Jimmy Carter spotted en route to DC Obama assembles his post-presidential team MORE said she supported gay marriage. 

The Supreme Court has heard two cases on the issue this year. Many expect the court will strike down the federal Defense of Marriage Act, which prohibits same-sex couples from getting certain benefits offered to married couples.

It's unclear whether more Senate Democrats or Republicans will shift their positions in the coming days. 

Manchin, Johnson and Pryor have expressed opposition to gay marriage, while Landrieu and Donnelly did not respond to requests for comment from Time, according to the publication's report. All five hail from states that Obama lost in the 2012 presidential election, though Obama did win Indiana in 2008.

Casey, Carper, Heitkamp and Nelson do not back same-sex marriage. All four have either opposed new legislation banning same-sex marriage or been clear proponents of civil unions and rights for same-sex couples.