(CNN) - New Jersey Gov. Chris Christie appointed his state's attorney general to temporarily fill the U.S Senate seat left vacant by the death of Sen. Frank Lautenberg.
The GOP governor, who made the announcement Thursday at a news conference at the state capitol in Trenton, introduced Jeffrey Chiesa, a fellow Republican, as his choice to temporarily succeed Lautenberg, the longtime Democratic senator who died Monday at age 89.
Christie also announced that Chiesa will not run in this year's special election to fill Lautenberg's seat.
Christie's decision changes the balance of power in the Senate, with the Democratic party's 55-45 majority (53 Democrats and two independents who caucus with the party) over the Republicans slipping to 54-46.
Christie praised Chiesa, who he's known for two decades.
"I said on Monday I was going to select the person I thought was going to be the best person to represent New Jersey between now and October 13," Christie told reporters. "During the last few days as I've gotten to deliberate on this decision, it became clear to me that Attorney General Chiesa would be the best person to represent the people of New Jersey in the United States Senate."
"I've appointed someone that I have great faith and confidence in and somebody I know almost as well as my own family," added Christie.
Chiesa served as executive director of Christie's transition then and then chief counsel to the governor from January 2010 through December 2011, when Christie nominated him to be attorney general. He heads to Washington on Monday.
Chiesa, who described himself as "a conservative Republican," said he'll have to learn quickly about the issues that he'll be voting on in the Senate over the next four months.
With the primary election just two months away, the first candidate in the race to succeed Lautenberg jumped into the race earlier Thursday.
The move by Democratic Rep. Rush Holt comes as a Democratic state senator in New Jersey vowed to introduce a bill that would move the date of the Garden State's November gubernatorial and legislative elections to the same day in October that Christie announced he would hold the general election in the special Senate contest.
Holt, a Democrat who's in his eighth term representing New Jersey's 12th Congressional District, said Thursday morning in a statement that, "I ask for your support as I seek to serve as your Senator in that seat. The reason is simple: I believe I am the best candidate to continue the passionate advocacy for progressive values that Sen. Lautenberg exemplified."
Although he has yet to make a formal announcement, Newark, New Jersey Mayor Cory Booker is collecting signatures to run in the special election. Spokesman Kevin Griffis confirmed the news to CNN, adding that "our volunteers are collecting signatures," which he said was consistent with the necessary steps they've been taking the past several months to prepare a candidacy. Candidates hoping to run in the race must hand in 1,000 signatures by 4 p.m. ET on Monday afternoon.
Booker, considered a rising star in the Democratic Party, earlier this year announced he was exploring a run for Senate in 2014. He made the news before Lautenberg, whose term was up in 2014, announced he would not run for re-election.
Rep. Frank Pallone, who's also considered likely to make a bid, has not made any announcements this week. A Democratic source with knowledge of Pallone's thinking tells CNN "an announcement will be forthcoming" but added that it would come after the late senator's funeral process is over, "out of respect to Lautenberg, who was a close friend to the congressman."
Pallone has the biggest war chest of the three men, with approximately $3 million cash on hand. Booker, who is seen as the favorite in the Democratic nomination battle, and who has the potential to raise a large sum of money thanks to his star power and national connections, currently has a smaller war chest than Pallone, with Holt having around $700,000 in the bank right now.
On the GOP side, former Bogota, New Jersey, Mayor Steve Lonegan says he'll run. Other possible candidates include Lt. Gov. Kim Guadagno, Rep. Jon Runyan, and biotech executive John Crowley. State senators Joe Kyrillos and Tom Kean Jr., who've both run for U.S. Senate in the past, seem to be leaning against making another bid this time around. Assembly Minority Leader Jon Bramnic has said he won't run.
Tuesday Christie announced that the Democratic and Republican primaries will be held on August 13, with the general election coming on October 16. The winner would serve the final 14-and-a-half months of Lautenberg's term. An election to a full six-year term will be held in November 2014.
Christie's announcement to hold the special Senate election in October was instantly slammed by both national and state Democrats. They argued that the move was a political ploy by Christie, who is up for re-election this November. Legislative elections are also being held in November. If the special Senate election were held on the same day it would most likely increase Democratic turnout in what's considered a blue state, especially if Booker is on the ballot.
By placing the special Senate election in October, Christie avoids Democratic turnout tied to this issue possibly becoming a problem for him.
But Democrats attacked him because of the cost of holding the special Senate election in October rather than waiting a few weeks till the already scheduled general election, saying Christie's wasting taxpayer dollars.
The New Jersey Office of Legislative Services estimates it will cost $12 million to state taxpayers to conduct such a general election.
Christie said Tuesday that state law only permits the option of an October special election or an election in 2014. And he added that "there's no political purpose" behind his decision on the election date.
"A $12 million cost, while not insubstantial, I don't think in the context of a $32 billion budget is something that should dissuade us from giving people an opportunity to get an elected United States senator down there as quickly as we can," added Christie Thursday.
A Democratic state senator, stating that "we've got to start thinking outside the box," says she'll introduce a bill as early as Thursday which would move the November general election to October 16, saving the taxpayers millions of dollars.
"This is at a time when we don't have money to waste" Sen. Shirley Turner told CNN, adding that she came up with the idea Wednesday.
Turner says the fellow Democratic lawmakers she's talked to are supportive of her move. She hopes to pass the bill through committee next week, with a vote by both houses of the legislature, which are controlled by the Democrats, before the current legislative session ends later in June.
A political adviser close to the governor, who asked to remain anonymous to speak more freely, told CNN that "we aren't surprised she (Turner) would introduce legislation solely for partisan gain."