It's the first big test for New Jersey Gov. Chris Christie's handpicked placeholder in the U.S. Senate.
Sen. Jeff Chiesa Thursday announced the he supports the sweeping immigration reform bill the chamber was scheduled to vote on later in the day.
In a statement, the Republican senator said "as a former Federal prosecutor and Attorney General for the State of New Jersey, I have looked carefully at this debate through the lens of public safety and law enforcement. This bill strengthens border security, E-verify and better identifies visa overstays through an improved entry/exit system. I will vote for this immigration bill because I believe it is the right thing to do."
Following the death earlier this month of longtime Democratic Sen. Frank Lautenberg, Christie named Chiesa as a temporary replacement to hold the seat until a special Senate election in October.
Steve Lonegan, who's considered the frontrunner in the August Republican Senate primary, opposes the immigration measure, which is supported by a bipartisan coalition of senators. In a statement, Lonegan said "this legislation is a pure and simple amnesty for illegal aliens and if I were a member of the U.S. Senate, I would vote no.
Christie, who's running for re-election this year and is considering a possible bid for the 2016 GOP presidential nomination, has not taken a stance on the legislation.
"Listen I haven't seen these bills, I've got enough to deal with here in New Jersey. I'm not interested in being a federal official," said Christie Wednesday night on his "Ask the governor" radio program.
And earlier this week, in a speech, Christie said that Chiesa is "his own man. He's going to make his own decisions. However he votes down there, I've told him this from the beginning, is up to him. I'm not going to tell him what to do."
Even though the measure bolsters security along the U.S.-Mexico border, it is opposed by many conservatives because of the provision which allows for an eventual pathway towards citizenship for most of the undocumented immigrants living in the country.
Since some pundits consider Chiesa a proxy vote for Christie, will the interim senator's stance on immigration reform hurt Christie in the conservative dominated primaries and caucuses, if the GOP governor decides to make a 2016 bid for the White House?
Republican strategist and CNN contributor Kevin Madden says he doesn't read too much into any one vote by an appointed interim senator.
"The short memory of this interim senator will be long gone before any 2016 voter begins to form a more certain opinion about Chris Christie and his position on immigration and other issues," says Madden, who was a top political adviser and spokesman to Mitt Romney in his 2008 and 2012 presidential campaigns.
Christie's standing with some on the right is already tenuous, due to the governor's continued defense of his appearance with President Barack Obama last year when the president came to survey the damage from Superstorm Sandy, just days before the November election. Some conservative critics slammed Christie, a major surrogate at the time for GOP nominee Mitt Romney, for standing side-by-side with Obama, arguing Christie, who served as a top surrogate for GOP nominee Mitt Romney, helped bolster the president's image shortly before voters took to the polls.
Since the powerful storm smashed into his state at the end of October, Christie has become the face of New Jersey's recovery efforts. He sought federal relief aid and sharply rebuked Republicans in Congress who voted against the aid bill at the beginning of the year. (Congress later passed more than $50 billion in relief funds.)
Christie, who again embraced a visit by the president in May, reminded the audience that he did not vote for the president and has policy disagreements with Obama, but added that whether "you voted for him or not, in this country we have one president at a time."