This state is one of the last strongholds for machine politics. That's about to change.

• New Jersey is one of the last states in the US with powerful party bosses and political machines.
• A key part of that machinery is the Garden State's unusual ballot design.
• But a judge blocked it for this year's Democratic primaries, and the change could become permanent.

New Jersey is one of the last places in the country where the phrases "party boss" and "political machine" don't just harken back to a bygone era, but describe a present-day reality.

In the Garden State, getting the endorsement of local party organizations — a process often controlled by political insiders — can make or break a primary campaign, thanks in large part to the way ballots are designed.

But that could all change forever, thanks to a lawsuit filed two months ago by Rep. Andy Kim, the all-but-certain Democratic nominee for Senate in the deep-blue state.

At the end of March, a federal judge sided with Kim, blocking Democrats from using the so-called "county line" system in the state's upcoming June primaries. That's set to bring a stark change to the way ballots look — and potentially, a total overhaul in the state's political culture.

Here's what to know about the "county line" and why it may be going away for good.

How the 'county line' steers votes

49 states use so-called "office-block ballots," in which candidates are simply listed beneath the name of the office they're seeking, without any sort of preferential placement.

That's not how ballots look in most of New Jersey.

In all but two of the state's 21 counties (Salem and Sussex), local party organizations are able to place all of their endorsed candidates in a single row or column. If you're not endorsed by the party, your name may appear somewhere off to the side, sometimes referred to as "Ballot Siberia."

You can see it in the example ballot from the 2020 Democratic primary below — Sen. Bernie Sanders is way off to the side, while then-candidate Joe Biden is on the same row as all of the other party-endorsed candidates.

Now, you may be thinking to yourself: Okay, but how does that help cement party control? There's nothing stopping anyone from voting for a candidate who doesn't show up on the line.

It's true that nothing's stopping people from voting for candidates that don't appear on the line. But it's a psychologically powerful tool, especially in elections where voters may not know very much about the candidates they're electing.

As Kim's lawsuit argues, candidates not endorsed by the party are "harder to find on the ballot, harder to know who they are running against and/or for what office, and may otherwise appear less legitimate on the ballot than the county line candidates."

Kim and his co-plaintiffs also provided proof in the form of academic research showing that candidates earned double-digit advantages when they ran on "the line," and that incumbents running on the line have almost never lost in recent decades.

It all began with Bob Menendez's gold bars and the short-lived primary to succeed him

In September, long-serving Democratic Sen. Bob Menendez was indicted by federal prosecutors in the most cartoonish scandal one could imagine: being accused of accepting bribes in the form of literal gold bars.

Menendez's political career effectively came to an end overnight, and Kim launched a campaign for his Senate seat just days after the indictment.

But Kim quickly became locked in a tough, personal primary with Tammy Murphy, the wife of Democratic Gov. Phil Murphy. Because of the power the governor wields over local officials, Tammy Murphy was expected to earn the endorsement of most county party organizations, putting Kim at a disadvantage when it came to the ballot.

That's what led the congressman to file his lawsuit in February, arguing that the system violated the US Constitution. US District Judge Zahid Quraishi ultimately agreed with Kim and issued a preliminary injunction blocking the system's use in the upcoming primary.

Murphy later dropped out of the race, all but assuring that Kim will win the Democratic nomination on June 4 and likely be elected to the US Senate in November.

The judge's decision, which applies only to Democratic ballots in the upcoming primary, has been upheld by a federal appeals court — and it signals that the old county line system is likely to be invalidated in future elections as another years-old lawsuit against the line continues to play out.

How the change could affect New Jersey politics in the coming years

While the decision means little for Kim at this point — he no longer has a major opponent — it could have a significant impact on other races in New Jersey, both this year and in the future.

Among them is a Democratic House primary between Menendez's son — Rep. Rob Menendez — and Ravi Bhalla, the mayor of Hoboken.

Proponents of the county line system have argued that it allows the party to serve an important gate-keeping function, keeping out ideologically extreme candidates who may lack institutional support.

Detractors point out that the system is anti-democratic, while arguing that it contributes to a culture of in which party bosses and the political establishment wield undue — and even corrupt — power.

"These ballot dynamics have predictable downstream effects that encourage backroom dealings and soft corruption, and they directly threaten election integrity, public confidence in our elections, and the fundamental premise of representative government," Kim's lawsuit argued.

In its absence, New Jersey's elections could begin to resemble those of other states.

"I think you'll see a more candidate-centric politics," said Jersey City Councilman James Solomon, a longtime opponent of the county-line system. "I think there are folks [in elected office in New Jersey] who have genuinely never run a real campaign. They've never had to raise money, they've never had to do field, they've never had to do comms."