WASHINGTON (AP) — Jeffrey Chiesa of New Jersey is the Senate’s newest member, but he’ll only be around for four months.

The 47-year-old Republican is taking his seat Monday after a swearing-in ceremony led by Vice President Joe Biden. GOP Gov. Chris Christie appointed his state attorney general to the seat last week after longtime Democratic Sen. Frank Lautenberg’s death.

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Chiesa is a longtime Christie colleague who will be interim senator until after an Oct. 16 special election. He won’t run in the special election to complete the term, which expires in January 2015.

Chiesa is the first Republican senator from New Jersey since another fill-in back in 1982.

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With Chiesa’s arrival, the Senate has 52 Democrats, 46 Republicans and two independents who often vote with the Democrats.

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