New Jersey first lady Tammy Murphy, Rep. Andy Kim running for embattled Sen. Bob Menendez's seat

New Jersey's Democratic primaries are heating up -- as two well-known Democratic candidates, that state's first lady Tammy Murphy and Rep. Andy Kim, are mounting primary challenges to longtime Democratic Sen. Bob Menendez, who faces an indictment and calls to resign.

An indictment in late September accused Menendez and his wife of accepting hundreds of thousands of dollars of bribes. Prosecutors filed a superseding indictment on Oct. 12 accusing Menendez of conspiring with his wife and businessman Wael Hana to have the senator act as an agent of Egypt. Menendez has pleaded not guilty.

Menendez has not said yet whether he will seek reelection, but denies wrongdoing and has not indicated any plans to resign from the Senate.

Murphy announced Wednesday morning that she is running for Menendez's seat. She entered the race with a launch video that does not reference Menendez by name, but calls out Washington lawmakers.

"Right now, Washington is filled with too many people more interested in getting rich or getting on camera than getting things done for you," she said in the video, alongside footage of congressional lawmakers, including Menendez. She then called out issues opposed by Republican lawmakers, such as abortion access and gun control.

In the video, Murphy highlights her efforts as first lady to reduce maternal mortality in the Garden State and to include climate change education in school curriculum.

Murphy previously worked as a banker and financier, and she has never held public office. She told the New Jersey Globe on Wednesday, "I don't have D.C. experience – I have New Jersey experience. And I would just say to you that whatever is happening in D.C. isn't working, so more people with D.C. experience is probably not what we need here and now."

Murphy's lack of political experience is a wildcard, Ashley Koning, director of the Eagleton Center for Public Interest Polling at Rutgers University in New Jersey, told ABC News.

"She's definitely known for positive initiatives in the state. She definitely has a credible and an important background. But again, obviously no political experience in terms of holding office and so it depends on how voters interpret that nowadays," Koning said.

Rep. Andy Kim, a Democrat who represents New Jersey's 3rd Congressional District, launched a Senate bid in September. He was the first significant Democratic official in New Jersey to call for Menendez's resignation after news of the senator's indictment broke.

Kim released a video Tuesday launching his Senate run, emphasizing his lawmaking experience and how his family motivates him to run. His video, which shows him speaking to focus groups of New Jerseyans, directly addresses Menendez's indictment.

"For me, being in public service demands the highest of standards… after he said that he's not resigning, that's when I decided to step up and challenge him," Kim tells voters in the campaign video.

In a statement to WABC-TV on Wednesday through his campaign, Kim wrote, "My message of integrity and changing our broken politics is connecting all across the state."

Progressive activist Lawrence Hamm is also running in the Democratic primary. He announced he was running in September.

"What will actually happen in terms of Kim versus Murphy? I think that's the question that's on everybody's minds right now," Koning said. She said that an upcoming Rutgers-Eagleton poll shows similar favorability ratings for both Kim and Murphy in the state.

"Kim declared first; he undoubtedly likely excited portions of the Democratic Party within the state. And otherwise, his claim to fame, obviously, being that iconic photograph of him cleaning up after Jan. 6 [2021] in the Capitol. And that's kind of emblematic of how he thinks about his political career," Koning said.

Murphy has already netted one key endorsement in the state -- at Menendez's expense. The Hudson County Democratic Organization, which represents Menendez's home county, endorsed Murphy on Wednesday, with the group's chair writing that it "is honored to give Tammy Murphy our full, unequivocal support."

Sources tell ABC News that Gov. Phil Murphy has privately intervened to get Democrats in the state to rally around his wife. Tammy Murphy's Senate campaign declined to comment to ABC News, and the office of Gov. Phil Murphy did not respond to a request to comment.

Koning said that Gov. Murphy may have legal and ethical considerations that impact how he can campaign for his wife.

At the same time, "she has been the right-hand person to her husband in many respects, throughout his tenure as governor… the big question is, will the county chairs fall for her, especially in the north, where she has more connections than Andy Kim does."

"It may actually be more difficult, potentially, for voters to swallow… than it would be for the county chairs to do. We don't know that yet. And obviously, there hasn't been any polling on that yet. But I would say, it will be a very interesting and, I think, delicately played race," Koning told ABC News.

Menendez released a statement Wednesday criticizing Tammy Murphy for previously being a registered Republican and for her connection to the governor. She voted in Republican primaries until 2014, according to the New York Times, which cited voting records. Separately, in September, Gov. Phil Murphy called for Menendez's resignation.

"Governor Murphy has said he won't appoint his wife to the seat, but why would he since there was never a need to? They believe they have to answer to nobody... While Tammy Murphy was a card-carrying Republican for years, I was working to elect Democrats up and down the ballot and fighting in Washington to deliver for hardworking families in New Jersey," Menendez wrote.

"From a broad perspective, in terms of Menendez, it's yet another nail in the political coffin for him," Koning said of Murphy's entry into the race, "where it does not look good in terms of [that] these are two political figures in this space that are very well known."

If Menendez's seat became vacant before the election in 2024, Gov. Murphy would be allowed to appoint someone to fill the seat, who would serve until the next time the seat goes up for reelection. Murphy could also, but is not required to, announce a special election for the seat, in which case any appointee from him would only serve until the winner of that special election gets sworn in.

Special elections for a New Jersey Senate seat have happened before. In June 2013, then-Gov. Chris Christie, a Republican, declared that there would be a special election -- and then appointed Jeffrey Chiesa to serve until the special election -- to fill the seat vacated by Democratic Sen. Frank Lautenberg upon his death. Chiesa decided not to run in the special election.

Koning said that it is unlikely that Gov. Murphy would call a special election if Menendez vacated his seat, because the seat is already up for election in 2024, and that Murphy would likely not appoint Tammy Murphy to the seat because of the ethical questions and optics surrounding that sort of move.

"It's a very unprecedented position now that we have a popular congressman now going up against the first lady, potentially, for this seat. I think for Menendez, it should really encourage him to just simply step down and not run for reelection. But we don't know that either. I think you have you have everyone's own political personalities at play right now," Koning said.

ABC News Brittany Shepherd, Josh Margolin, Isabella Murray and Aaron Katersky contributed to this report. WABC-TV's Mark Crudele contributed to this report as well.