Republican U.S. Rep. Tom MacArthur's second-floor Marlton office was roped off, with a sign reading: "Consultations by Appointment Only."

Andy Kim, MacArthur's Democratic challenger in New Jersey's Third District, did not have an appointment, but staged a rally against the incumbent and special-interest money in politics down the hall last week.

Referring to MacArthur as the "17th richest member of Congress," he said, "It makes me disgusted," to see "just how bad our politics have gotten." Kim called the former insurance executive "a dangerous man."

In his own ads, MacArthur has called Kim a liar, a resumé embellisher, and a tax cheat. Ads paid for by Republican super PACs conclude about the Marlton native whose parents immigrated from South Korea: "He's not one of us."

In the Third District, which awkwardly marries the congested Philadelphia suburban communities of Burlington County with the gone-to-retire Shore towns of Ocean County, the punches are landing fast and furious.

A true swing district, the Third voted for Barack Obama twice, and Donald Trump won it in 2016. Yet it has mostly been represented by Republicans in Congress in the last 20 years.  Democrats have targeted it as a pickup opportunity in the midterm battle for House control.

Those stakes create an incentive for negative attacks. Republicans in tight races have been trying to disqualify Democrats in voters' eyes. And as a challenger, it pays for Kim to tie MacArthur to the president, who has lost popularity.

In New Jersey, it’s taxes vs. everything 

Democrats believe they have a vulnerable target, the only New Jersey congressman — of either party — to vote yes on the GOP tax bill, which caps deductions on state and local taxes (SALT), and who authored his own health-care amendment that revived Republican efforts to repeal Obamacare.

"He had no cover from anybody," said Rutgers political science professor Ross Baker.

According to the Wesleyan Media Project, which tracks political advertising, 63 percent of the 3,680 political ads in New Jersey federal races that ran during August mentioned taxes as an issue.

That percentage was the highest of any state.

Congressman Tom MacArthur meets with members of the editorial board and reporters at the Philadelphia Media Network office on Tuesday, Sept. 25, 2018.
Heather Khalifa
Congressman Tom MacArthur meets with members of the editorial board and reporters at the Philadelphia Media Network office on Tuesday, Sept. 25, 2018.

"If you live in Jersey, that MacArthur tax bill, taking away state and local deductions, that really hurts people in New Jersey," said Rich Gilligan of Marlton, a retired corporate ethics officer volunteering for Kim. "This is the first time I've knocked on doors my entire life."

Baker believes MacArthur's attempts to be central to the action in Washington, both on taxes and health care,  have come at a political cost.

"Some people when they arrive in Congress as middle-aged people used to being in executive positions really want to be in on the action and they put their foot to the accelerator and become players," Baker said. "Had MacArthur not been so publicly identified with the tax reform and had that not had the SALT cap, he'd be cruising to an easy victory."

‘Real Fishy’ vs Dreaming of an ‘Age Tax’? 

The day after the rally, a new ad against MacArthur began running, paid for by the League of Conservation Voters Victory Fund, complete with smokestacks over soccer-playing children, black-and-white glimpses of MacArthur as the "architect" of the health-care repeal law, children gasping through oxygen masks, with the variation on a theme tag line: Tom MacArthur: Not for us.

MacArthur hasn't pulled punches against Kim, who worked in national security under President Barack Obama (and, though briefly, under President George W. Bush, a boast that earned him two Pinocchios from Washington Post fact checkers, followed by a MacArthur attack ad, for equating those five months with his much more extensive service under Obama).

Paul Ryan's Congressional Leadership Fund super PAC, which produced "Not One of Us," committed $1.4 million on behalf of MacArthur and set up a field office in the district.

On Aug. 27, CLF announced a new ad upping the attack ante on Kim from "tax cheat" to "tax raiser," for opposing Trump's "middle class tax cut."

For MacArthur's part, he has complained about an attack mailer that blames him as author of an "age tax," as documented by InsiderNJ. The mailer shows MacArthur sleeping with cash under his pillow.

"Have you seen that one?" MacArthur said. "That is a lie. This is the season where there's a lot of political lies."

Kim's campaign said it was not responsible, though it then sent out a press release using "age tax" to refer to MacArthur's Obamacare repeal proposal. AARP coined the term, saying the bill would have allowed insurers to charge people aged 50 to 64 up to six times more than younger adults for coverage.

House Majority PAC, a Democratic super PAC, sent the "age tax" mailer, it turns out. The group said it has spent $1.2 million on ads against MacArthur.

The "Just Not for Us" ad is part of a nearly $1.1 million effort by the League of Conservation Voters and other environmental groups including ads, digital targeting, and canvassing.

Amy Goldsmith, state director of Clean Water Action, said the group has knocked on doors of 20,000 households in the district, which includes Toms River, on behalf of Kim.

Some attacks have misfired: Democratic National Committee chair Tom Perez criticized MacArthur at this month's state convention in Atlantic City for his response during Hurricane Sandy, which devastated parts of the district in 2012, two years before MacArthur was elected to Congress.

Soundproof booth

Hours after his rally at MacArthur's office building, Kim's campaign released a new ad.

It was called "Booth," and had a decidedly different tone than the last Kim ad, a soft biographical spot called "Service."

A man enters a soundproof booth at a packed town hall, Kim narrating about special interests drowning out citizens.

"Feel like Republicans can't hear you?" Kim says. The suit in the booth then grabs at dollars flying by.

"Look at Tom MacArthur," he says, as the incumbent's face is superimposed on a bill. "He took over $400,000 from drug and insurance special interests and wrote their bill," Kim says, referring to the health-care repeal proposal. He says he hasn't taken "a dime" from corporations.

Patrick Murray, the Monmouth University pollster, said Kim has to go negative to beat the incumbent.

"It's like running a business. You don't fire an employee because someone comes along you might like better," Murray said. "You have to consider whether you want to fire this employee."