A federal judge on Friday overturned New Jersey’s county organizational line for the upcoming primary, a move that could have major implications for elections in the state.

U.S. District Judge Zahid N. Quraishi granted a request for a preliminary injunction from Democratic Rep. Andy Kim, who is running for Senate, to overhaul the state’s ballot design. The line has long given preferential ballot placement to candidates backed by powerful county organizations, making it difficult to oust incumbent lawmakers.

In his opinion, Quraishi said he recognized “the magnitude” of the decision.

“The integrity of the democratic process for a primary election is at stake and the remedy Plaintiffs are seeking is extraordinary,” Quraishi wrote in the 49-page opinion. “Mandatory injunctive relief is reserved only for the most unusual cases. Plaintiffs’ burden on this Motion is therefore particularly heavy. Nevertheless, the Court finds, based on this record, that Plaintiffs have met their burden and that this is the rare instance when mandatory relief is warranted.”

Kim filed the lawsuit last month when the race for the Democratic Senate nomination was more crowded. After his chief rival, New Jersey first lady Tammy Murphy, dropped out of the race last Sunday, Kim appeared on track to win the nomination. Democrats Patricia Campos-Medina, a labor leader, and Lawrence Hamm, a perennial candidate, are also on the ballot for the June 4 primary.

Democrats Sarah Schoengood, who is running for Kim’s 3rd District seat in the House, and Carolyn Rush, who is running for the 2nd District seat currently held by GOP Rep. Jeff Van Drew, also brought the lawsuit with Kim.

“Today’s decision is a victory for a fairer, more democratic politics in New Jersey. It’s a victory built from the incredible grassroots work of activists across our state who saw an undemocratic system marginalizing the voices of voters, and worked tirelessly to fix it,” Kim said in a statement.

Kim launched his Senate campaign the day after Sen. Bob Menendez, the Democrat who currently holds the seat, was indicted in September on federal bribery charges and was accused of acting as a foreign agent. Murphy, whose husband is Gov. Phil Murphy, later got in the race with significant Democratic support, including much of the state’s congressional delegation.

But grassroots support for Kim swelled. He won the line in nine conventions, including in Murphy’s home county of Monmouth along the Jersey Shore.

Menendez, who along with his wife and three New Jersey businessmen is under federal indictment, said that he wouldn’t run in the Democratic primary, although he left open the possibility of running as an independent in the general election. He has maintained his innocence and is set to face trial in early May.

Still, Menendez’s approval ratings have gone down since the charges were unveiled in September, along with photos of cash and gold bars found in his home, allegedly the payoff from the businessmen.

Menendez’s son, freshman Rep. Rob Menendez, faces a primary challenge from Hoboken Mayor Ravi Bhalla, who had more cash on hand than the younger Menendez in his House campaign account at the end of December, according to Federal Election Commission filings.

Rob Menendez had the backing of Democratic organizations in three counties for the 8th District. If Friday’s ruling stands, that primary could become more competitive.