Four Democratic senators facing tough reelection fights voted in favor of the immigration reform measure on Thursday afternoon, opening themselves up to likely attacks from conservatives heading into 2014 and beyond.
Sen. Al FrankenAl FrankenSenate passes resolution honoring Prince Senators aim to bolster active shooter training Minnesota senators praise Prince on Senate floor MORE (D-Minn.), who is also up for reelection but considered less vulnerable, also voted for the bill. No Democrats voted against the legislation.
A handful of Republicans in blue and swing states — some of who could see primary challenges — voted for passage.
He has long faced criticism from conservatives for his record, though no primary challenger has yet emerged, and he's long been an outspoken supporter of reform.
Sens. Kelly AyotteKelly AyotteGOP women push Trump on VP pick John Bolton PAC pours more cash into GOP campaigns Dem campaign arm: Poll numbers slipping for vulnerable Republicans MORE (N.H.), Marco RubioMarco RubioRubio: Trump has 'improved significantly' House GOP campaign arm accuses '60 Minutes' of trespassing Republicans who vow to never back Trump MORE (Fla.) aren't up for reelection until 2016, but their support for the reform measure is already causing consternation among conservatives.
Most notably, Tea Party leader Sarah Palin suggested the two should face primary challenges.
And Rubio, who is seen as a probable 2016 contender, has seen his poll numbers drop in the past month, as debate over the bill intensified.
Critics say his role in crafting and selling the measure to the public could hurt him with Republican primary voters and jeopardize his presidential aspirations.
Also up for reelection in 2016 is Sen. Mark KirkMark KirkElizabeth Warren stumps, raises funds for Duckworth GOP blocks slate of Obama judicial nominees Durbin: McConnell should move criminal justice bill next month MORE (R-Ill.), whose vote for the bill could help him appeal to centrist voters in his blue state.
Sen. Dean HellerDean HellerCarter pledges probe of sex assault testimony Democrats block energy spending bill over Iran amendment Senate votes to increase wind energy funding MORE (R-Nev.), up in 2018 in a swing state, will also need to appeal to that voting bloc.
GOP debate over the bill has highlighted a split within the party on reform. Conservatives generally oppose what they say is a temporary stop-gap measure that does little to solve the problem and offers inadequate border security provisions.
The no-votes from National Republican Senatorial Committee Chairman Jerry MoranJerry MoranOvernight Finance: McConnell fast-tracks IRS bills; WH pushes free college tuition The Trail 2016: New Trump same as the old GOP lawmaker passes on Kansas Senate primary challenge MORE (Kans.) and his NRSC deputies, Sens. Rob PortmanRob PortmanJohn Bolton PAC pours more cash into GOP campaigns Dem campaign arm: Poll numbers slipping for vulnerable Republicans GOP senator jokingly calls Sherrod Brown 'Mr. Vice President' MORE (Ohio) and Ted CruzTed CruzCruz condemns Trump protesters: These are tactics of left-wing agitators Trump predicts easy win in November Sanders-Warren ticket would sweep the nation MORE (Texas), underscore what a politically perilous issue immigration may be for some Republicans going forward.
In the House, a large contingent of far-right members have pledged to oppose the Senate measure.