Democrats are campaigning on protecting democracy. In N.J., what that means is complicated.

TRENTON, N.J. — On Sunday evening, Democratic Rep. Andy Kim celebrated a decisive win at the Atlantic County Democratic Committee’s convention, giving him an advantageous position on the county’s ballot in the June 4 Senate primary.

The next day, Kim took the witness stand here in federal court, fighting against that very ballot position.

“It’s about what kind of democracy we want here in New Jersey,” Kim told NBC News after he testified Monday.

It’s a broad statement about an esoteric local political custom — one that has become one of the defining issues in a Senate primary with few major ideological divides.

Kim filed a lawsuit last month seeking to eliminate the so-called county line, a unique ballot design in which party-endorsed candidates appear bracketed together in a single column on the primary ballot, and nonendorsed candidates appear off to the side. Instead, Kim wants candidates grouped by office, arguing the county line is unconstitutional since it gives party-backed candidates an unfair advantage over outsiders.

In some counties, the party chair is the endorsement’s sole arbiter. Several of those chairs endorsed New Jersey first lady Tammy Murphy a few days after she launched her Senate campaign in November, sparking criticism that they were looking to curry favor with Gov. Phil Murphy, the state's top Democrat. The parties in other counties, like Atlantic, award endorsements through convention votes.

The clash over the county line, which is used in all but two of the state’s 21 counties, comes as Democrats across the country are campaigning on protecting democracy. But some Democrats say that message is more complicated in New Jersey, where party bosses still wield significant power.

“New Jersey is nicknamed the Soprano state, and it’s for a good reason,” said Sue Altman, a Democrat running for Congress in the 7th District who led the New Jersey Working Families Alliance and has clashed with party power brokers.

“It would make the campaign much easier and much more straightforward if we could stand up tall and proud and say, ‘Yes, at every level Democrats are the party of democracy and have the receipts to back that up,’” Altman later added. “But right now in New Jersey that’s difficult to do.”

Kim said that taking on the party machine is critical for Democrats trying to hold onto Sen. Bob Menendez’s seat. Menendez, who was indicted in September on bribery charges, announced Thursday he might run as an independent if he is exonerated.

“Right now, independent voters are very wary of the Democratic Party here in New Jersey after this indictment of Sen. Menendez,” Kim said in an interview at the Atlantic County convention on Sunday.

“If it looks like the same political machine that protected Menendez for so long is trying to shape the outcome of this Senate primary, independent voters are not going to stand for that,” Kim later added.

Process, policy and the campaign

Tammy Murphy, meanwhile, is looking to stay focused on policy issues.

“We’re all playing by the same rules. So if the rules get better, if they can reform and make things better, then I’m all for that,” Murphy told NBC News after meeting with union members in Mays Landing on Sunday, where she touted her work as first lady on issues like raising the minimum wage and improving infant and maternal health care.

“But my view is — that’s over here,” Murphy added. “I’m trying to help with affordability. I’m trying to help with reproductive freedoms. I’m trying to help with gun safety and climate change. And I think that’s what people really think about every single day. So I am sick of hearing about the process.”

Still, some New Jersey politicos said questions about the process have consumed the race.

“The county line dynamic that we’re even talking about now has overshadowed the core of any campaign,” state Democratic Party Chairman LeRoy Jones Jr. said in a phone interview.

Jones, who also chairs the Essex County Democratic Committee, is among the leaders who endorsed Murphy. Jones has the sole power to decide which candidate is on the ballot line in Essex, but he said he surveyed the roughly two dozen municipal chairs in his county before endorsing the first lady.

Kim said a number of county chairs who ultimately backed Murphy did not return his phone calls. After Murphy launched her run, Kim faced pressure to drop out.

“I don’t want to go into specific names, but I had a number of people tell me that they think my chances are zero,” Kim said Sunday. Kim said he told one of them, “I don’t think I can look my two kids in the eye if I drop out of this race simply because someone who’s more connected than me is jumping in, but somebody I think that I have more experience than.”

Pressures in the convention process

Kim hasn’t been the only one facing pressure to fall in line.

Sadaf Jaffer, a former assemblywoman and mayor of Montgomery Township, said she was pushed not to nominate Democrat Patricia Campos-Medina for Senate at her party convention in Somerset County, where the chairwoman, Peg Schaffer, had endorsed Murphy.

Jaffer said in a phone interview that someone with the county party “pulled me aside and said, ‘Don’t hurt your future. Don’t do something to hurt your future.’” Jaffer declined to name the individual, but said it was not Schaffer. Murphy won the Somerset County endorsement, which was decided by a public show of hands.

Campos-Medina was also physically barred from entering the Camden County Democratic meeting on Saturday, where Murphy received the endorsement. Kim said his requests to attend the meeting were rejected.

“This goes against our message of protecting democracy,” Kim said at the Atlantic convention on Sunday.

“You’ll have to talk to Camden,” Murphy told reporters at the convention when asked about Saturday’s meeting. “I think we all have been playing by the same rules in the counties.”

Those rules can benefit some candidates over others in a primary, according to research from Rutgers University professor Julia Rubin, who also testified as an expert witness in Kim’s lawsuit Monday.

Candidates not on the line “look illegitimate” when they are not grouped with other candidates, Rubin said in a recent phone interview. “They’re off in ballot Siberia.”

The Camden County primary ballot from 2018 illustrates how the line can favor the favorite, with Democratic Rep. Donald Norcross' opponent squished on the far right side of the ballot after lines of empty space.

Micah Rasmussen, director of the Rebovich Institute for New Jersey Politics at Rider University, was doubtful Kim would face that significant of a disadvantage over the county line system.

“If [Kim’s supporters] have to bring a magnifying glass to find him on the ballot, they’re going to find him,” Rasmussen said.

Although the county endorsement process is nearly complete, the primary race is still heating up. Neither candidate has spent much money so far, although Murphy recently launched a TV ad focused on gun violence.

Murphy is ready for the county endorsement process to be over. She focused on other issues as she met with several members of Unite Here Local 54, which represents hospitality workers, in the back of a Mays Landing bar on Sunday afternoon.

Aura Sprague, a 54-year-old union leader and former hostess from Harbor Township, said she plans to support Murphy in the primary.

“It’s not what she said, but it’s also her actions,” Sprague said. “I mean, she’s a person that has been a direct friend with our union members, and she has been for us through the years.”

But Kim’s supporters believe he is more qualified to serve in the Senate, citing his three terms in Congress and his work as a foreign affairs officer in the State Department.

”He is a dedicated public servant,” said Christi Davis, a retired environmental engineer from Woodbury Heights, who stood outside of the courthouse on a chilly Monday morning with other activists, holding a sign that read, in part, “Abolish the line."

Davis said she became involved in the anti-line movement when she saw several powerful county chairs endorse Murphy.

“It’s just too obviously rigged," she said.