Those contests have been largely quiet.
Not so, the fight to succeed Runyan. Even the former NFL mauler was taken aback by the vitriol.
The race has featured a defamation lawsuit (by MacArthur) and charges (by Lonegan) that the insurance firm MacArthur built shortchanged disaster victims.
Lonegan, a longtime conservative firebrand and former mayor of Bogota in Bergen County, has relentlessly attacked.
"I'm the conservative - my opponent is the establishment liberal who will go to Washington, D.C., and give us more of the same," Lonegan, 58, said in an interview. "This is a battle in New Jersey for what's going to define the Republican Party."
MacArthur, 53, has won support from Runyan and party leaders in Burlington and Ocean Counties, and has held double-digit leads in recent polls.
He has pointed to Lonegan's opposition to a federal relief package after Hurricane Sandy - even though the district was hard hit by the storm - and accused Lonegan of using "the language of someone who wants to make noise but can't get anything done."
"Part of the job of leaders is to find the common ground, find the give-and-take, and do things that advance the country and advance the economy," MacArthur said.
Like Lonegan, MacArthur is new to the district, which covers much of Burlington and Ocean Counties. Until recently he was the mayor of Randolph, in Morris County. He moved to Toms River before the race, while Lonegan purchased a home in Lavallette.
The South Jersey seat has long been held by Republicans - a Democratic victory in 2008 being a lone recent exception - but it remains competitive. President Obama carried the district twice.
National Democrats have made the race one of their top priorities, and local Republican leaders say Lonegan's views don't fit the moderate district.
"I personally don't think Lonegan can carry this seat in a general election," Runyan said. "He's way too abrasive."
Fired back Lonegan: "That's what liberals say about conservatives all the time - conservatives who want to end the welfare state."
While there are policy differences between the two - Lonegan, for example, wants to repeal Obama's health law and leave health-care reform to the private market; MacArthur wants the law repealed but replaced with state insurance programs for people who can't find coverage - the sharpest contrasts have been in approach and tone.
"Republicans are tired of wishy-washy leadership going down to Washington, compromising with Obama," Lonegan said.
When Sarah Palin endorsed him on her Facebook page, she called Lonegan "the type of conservative leader we need."
MacArthur said governing requires holding true to principles but realizing that "other people have principles too."
MacArthur leads the money race, thanks almost entirely to $2 million he gave his campaign. Lonegan touts his grassroots support, made up of many more donors, and points out that he won 54.5 percent of the vote in the district last year in a Senate campaign against Democrat Cory Booker.
The winner of their race will take on either Edgewater Park's Aimee Belgard, a 40-year-old Burlington County freeholder backed by national Democrats, or Lakewood lawyer Howard Kleinhendler, 51. They are competing in the Democratic primary.
If Belgard prevails, she will be one of two general-election candidates with a viable chance to become New Jersey's first woman in Congress in more than a decade, said Brigid Harrison, a Montclair State University political scientist.
A woman is also likely to emerge as the favorite after a primary in a heavily Democratic central New Jersey district.
In another South Jersey district, sprawling from Atlantic City to Cape May to Camden County, 10-term Republican Rep. Frank LoBiondo, 68, is being challenged in a primary by Mike Assad, 26, an Atlantic City resident who also ran in 2012.
The Democratic establishment is backing a familiar name: William Hughes Jr., a Northfield defense lawyer and son of Congressman William Hughes, who held the seat for 20 years before LoBiondo. Hughes Jr., 47, faces opposition from Dave Cole, 29, a software engineer and former Obama administration aide from Sewell.
An open seat based in Camden County - vacated in February by longtime Democratic Rep. Robert E. Andrews - has drawn seven contenders.
State Sen. Donald Norcross of Camden has the support of the region's most powerful Democrats, and a massive fund-raising lead. He is the favorite in a heavily Democratic district, facing primary competition from Logan Township Mayor Frank Minor, 59, and retired Marine Frank Broomell, 27, of Sicklerville. Norcross, 55, is the brother of political power broker George Norcross, who sold his interest in The Inquirer last week.
Local Republican leaders in the district are backing another ex-Eagle, Garry Cobb, 57, of Cherry Hill. Four other Republicans are running against him: former Collingswood board of education member Claire Gustafson, 62; Gibbstown's Lee Lucas, 56, a repairman; and Berlin Realtor Gerard "Jerry" McManus, 47.
Republicans statewide will also choose between four candidates running for the right to challenge Booker. None of the candidates have held public office, though they have made nearly a dozen combined bids.
Jeff Bell, 70, is running after long living in Virginia but renting a home in Leonia shortly before declaring his candidacy. He defeated New Jersey's last Republican elected senator, Clifford Case, in a 1978 primary, but then lost to Democrat Bill Bradley.
Also running are Brian Goldberg, 41, of West Orange, general manager of a concrete company; Freehold resident Richard Pezzullo, 56, owner of a computer consulting company and a frequent candidate for state and federal office; and Murray Sabrin, 67, a professor at Ramapo College who has run for governor once and the U.S. Senate twice.
New Jersey's top Republican officials all passed on the race.