Representative Andy Kim, a lawmaker who has turned New Jersey politics on its head since entering the race to unseat Senator Robert Menendez, won the Democratic nomination for Senate on Tuesday after a campaign marked by a watershed ballot-access ruling.
The victory makes Mr. Kim, 41, a favorite to become New Jersey’s next senator. He would be the first Korean American to be elected to the U.S. Senate.
“I’m humbled by the results,” Mr. Kim told reporters gathered at Terhune Orchards in Princeton on Tuesday night. “This has been a very challenging and difficult race, a very dramatic one at that, and one that frankly has changed New Jersey politics forever.”
The results, announced by The Associated Press minutes after polls closed, capped a tumultuous campaign that began a day after Senator Menendez, a Democrat, was accused in September of being at the center of a sprawling international bribery scheme.
The senator’s criminal case thrust his son, Representative Rob Menendez, 38, into a suddenly competitive race for re-election to a second term. But the younger Menendez managed to hold on, winning a Democratic primary over Ravi Bhalla, the mayor of Hoboken, N.J., by a decisive margin.
“This is about showing that you’re resilient in the face of challenges,” an exuberant Mr. Menendez told supporters crowded into a beer hall in Jersey City, N.J.
“Whatever questions people had about me,” he added, “we answered them tonight. We earned this election.”
Mr. Kim, a former member of the National Security Council who advised President Barack Obama on Iraq, was first elected to Congress in 2018 — one of four Democrats that year to flip a New Jersey district from red to blue after Donald J. Trump was elected president.
For months, his main Senate opponent had been Tammy Murphy, the wife of Gov. Philip D. Murphy. Ms. Murphy, a first-time candidate, was bombarded by accusations of nepotism and dropped out of the race in March after failing to connect with voters.
His victory on Tuesday came as Senator Menendez, 70, was in his fourth week of a federal trial in Manhattan, defending himself against some of the most serious charges ever leveled against a sitting member of Congress.
The senator did not compete for the Democratic nomination, but on Monday he took steps to have his name imprinted on a ballot at least one more time by filing to run for re-election in November as an independent.
Voters said Tuesday that they were skeptical he had any political future at all.
“He’s done for — he’s not going to win anything,” June Ackermann, 67, a nurse from Freehold, N.J., said. She said she had cast her ballot before Tuesday, during the early voting window, in part because politics had “gone upside-down crazy.”
Ballots were also cast Tuesday in primary elections for president and 11 of the state’s 12 seats in Congress. (A special election will be held in September for the House seat once held by Representative Donald M. Payne Jr. of Newark, who died in April.)
Many of the races were directly affected by Senator Menendez’s legal trouble, as well as a court decision that changed the rules governing how Democratic candidates would be listed on the state’s primary ballots.
Mr. Bhalla had cast Mr. Menendez as part of the same broken machine politics that his father has come to embody. But Mr. Menendez’s constituents in the Eighth Congressional District appeared willing to draw a distinction between father and son. With nearly 80 percent of the votes tallied, he was ahead of Mr. Bhalla by a margin of 54 to 35 percent.
In the Senate race, Mr. Kim’s margin of victory was also decisive. With 71 percent of the votes tallied, he had more than 75 percent of the vote, according to the A.P. He beat two left-leaning Democrats, Patricia Campos-Medina, who came in second with 16 percent of the vote, and Larry Hamm, who got about 9 percent.
Curtis Bashaw, a hotel developer from Cape May, N.J., won the Republican primary. With 67 percent of the vote tallied, Mr. Bashaw had 48 percent of the vote. His nearest competitor, Christine Serrano Glassner, the mayor of Mendham Borough, N.J., had 37 percent.
Mr. Bashaw, 64, is a political moderate who has expressed support for Mr. Trump, who continues to hold sway over the Republican base in left-leaning New Jersey. He will face a tough race against Mr. Kim in November.
It has been 52 years since New Jersey voters elected a Republican senator; Democrats hold a 930,000-person registration advantage, and Mr. Trump lost to President Biden in New Jersey by 16 percentage points in 2020.
Senator Menendez’s entry into November’s race as an independent has the potential to offer Republicans a boost, however, by fracturing the Democratic vote. Mike Berg, a spokesman for the Republicans’ national campaign operation, said Monday that the party was “keeping a close eye on New Jersey.”
The senator’s reasons for running may have little to do with re-election. By remaining in the race, Mr. Menendez can continue to collect campaign contributions to supplement the $3.5 million he had on hand as of last month. He has already spent more than $3 million on his current team of lawyers, and the trial is expected to last for at least another four weeks.
The senator is also using his campaign account to pay lawyers representing his wife, Nadine Menendez, who is also charged in the bribery conspiracy and is expected to stand trial this summer.
Mr. Kim’s decision to run for the Senate meant that, win or lose, he would have to vacate his House seat in a South Jersey district redrawn after the 2020 census to favor Democrats.
On Tuesday night, a state assemblyman, Herb Conaway, 61, won the Democratic primary to replace him. With 67 percent of the votes tallied, Mr. Conaway was beating his chief rival, Carol Murphy, by a margin of 48 to 25 percent.
Mr. Conaway, a physician who also has a law degree, was first elected in 1997. He was endorsed by several Democratic county organizations. In past years, that would have afforded him a prominent spot on the ballot, known as “the county line.”
But a legal challenge Mr. Kim filed in February has fundamentally reshaped electoral politics in New Jersey.
Siding with Mr. Kim, a judge ordered Democrats to stop grouping all candidates endorsed by the county political party in a single line on the ballot and to instead present the names of candidates running for each office together.
Representative Menendez was elected to a first term in 2022. He had never held office before then but was able to clear the field on the strength of his father’s connections — even before he announced he was running.
This election, the political landscape was far different. After Senator Menendez was indicted last year, Mr. Bhalla, the first Sikh to lead a New Jersey city, jumped into the House race. He emphasized Representative Menendez’s connections to his father and outpaced the congressman in fund-raising.
Representative Menendez won the endorsements of the state’s leading Democrats, including the governor, who brought with them a well-oiled party apparatus skilled at getting out the vote.
Brian Stack, a state senator and the mayor of Union City, N.J., introduced Representative Menendez at his victory party, noting that the freshman congressman had won — even without the so-called line.
Mr. Bhalla, 50, congratulated his opponent, and said that the race itself “shook up the system.”
He said it was important to “make sure elections are dictated by the people — not party bosses.”
Elise Young and Erin Nolan contributed reporting.