With a big win by Christie looming, Democrats "got out in front of it," touting an ability to work with the Republican governor, Murray said.
Democrats - and special-interest allies - also dumped money into key districts, staving off Republican challengers.
Independent spending has shattered records this election, with groups supporting Democrats outspending those backing Republicans by a 2-1 ratio, according to the Election Law Enforcement Commission (ELEC).
By the middle of last week, outside groups - barred from coordinating with candidates - had spent $38 million on state races and ballot questions, according to ELEC. The previous record for outside spending was $14.9 million in 2009, when Christie defeated Democratic Gov. Jon S. Corzine.
Tuesday's election ranks sixth among the 10 most expensive state elections fueled by independent spending since 2006, according to ELEC.
"We already are in the top 10 state races of all time, and the election still isn't over," said Jeff Brindle, executive director of ELEC, who called the spending "mind-boggling."
The biggest spender so far is Garden State Forward, a super PAC formed by the New Jersey Education Association, which has spent $12 million, according to ELEC.
Other top spenders include the Committee for Our Children's Future, which spent $7.8 million in support of Christie but which has not been active in the general election, and the Fund for Jobs, Growth and Security, a Washington-based super PAC formed this year to help Democrats in state legislative races.
The group, which has spent $7.6 million on legislative races and $680,000 on the minimum-wage ballot question, has received fund-raising help from South Jersey Democratic leader George E. Norcross 3d, according to a Democratic source.
Norcross, a part-owner of The Inquirer, declined to comment.
Candidates also are spending big in the elections. Three of the priciest races in the state are in South Jersey, starting with the battle headlined by Senate President Stephen Sweeney (D., Gloucester) and Republican Niki Trunk in the Third District, where candidates have raised $3.6 million.
Targeting Sweeney, Senate Minority Leader Thomas Kean Jr. has funneled money into Trunk's campaign. Trunk - a lawyer whose farmland tax exemption was the subject of an attack ad by the Fund for Jobs, Growth and Security - has run ads blasting Sweeney as a bully.
The race also pits Assemblyman John Burzichelli and Assemblywoman Celeste Riley, both Democrats, against Republican Gloucester County Freeholder Larry Wallace and Salem County Freeholder Bob Vanderslice.
Riley may be one of the few Democrats to lose her seat, Murray said. Christie is predicted to win big in the Third District, which encompasses Salem County and parts of Gloucester and Cumberland Counties. It's unclear whether Riley can pick up ticket-splitters, Murray said.
Other South Jersey races that rank among the priciest are the First District, spanning Cape May County and parts of Atlantic and Cumberland Counties, and the Second District, which includes part of Atlantic County. Economic issues have been central to the races.
In the Second District, Republican Atlantic County Sheriff Frank Balles is challenging Democratic Sen. Jim Whelan, a fixture in local and state politics. Republican Assemblymen John Amodeo and Chris A. Brown face Democratic Mayors Nick Russo of Longport and Vince Mazzeo of Northfield.
In the First District, Republican Susan Adelizzi-Schmidt, owner of a marketing business, is attempting to unseat Sen. Jeff Van Drew. Assemblymen Nelson Albano and Bob Andrzejczak, both Democrats, are competing with Cape May County Freeholder Kristine Gabor and Cumberland County Freeholder Sam Fiocchi.
At the local level, Democrats are trying to take control of the Burlington County freeholder board for the first time in three decades, with Democrat Reva Foster of Willingboro taking on Republican Burlington County Freeholder Director Joe Donnelly. Camden and Gloucester Counties also have freeholder races.
In Camden City, the four candidates fighting to unseat the Democratic Party-backed mayor, Dana L. Redd, squared off at a debate Friday on how to bring jobs and economic development to the city.
Voters in 501 school districts will choose school board members Tuesday, a relatively new occurrence. A law passed in 2012 let districts move their annual elections from April to November to increase voter participation. Since the change, the number of school board candidates per vacant seat has declined slightly, according to the New Jersey School Boards Association.
Also on Tuesday's ballot: questions to raise the state's minimum wage by $1 to $8.25 an hour and tying future increases to inflation, and to allow veterans groups to use money from games of chance for their operating costs instead of charitable purposes.
The minimum-wage question has spurred the formation of campaigns on both sides of the issue, featuring ads and voter outreach. Veterans organizations also have been trying to spread the word.
"A lot of people when they go to the polls, they'll start at the top. . . . When they look at the bottom and see a ballot question, they automatically hit no," said John Baker, department adjutant for the American Legion Department of New Jersey. "We're trying to educate the general public: Help the veterans groups out."