It has been described as a “clash of the titans” or, somewhat less flatteringly, like watching “two ageing lions claw at each other”.

In a bitter contest the likes of which only New York could possibly stage, two veteran Democrat members of Congress – 75-year-old Jerrold Nadler and 76-year-old Carolyn Maloney – have been forced by boundary changes into an electoral duel to represent one of America’s most Jewish districts.

Tomorrow’s primary may also mark a historical turning point: if Mr Nadler is defeated, New York will have lost its last remaining Jewish member in the House of Representatives.

Thirty years ago, the city – home to the US’ largest Jewish population – sent eight Jews to Congress. (A number of Jewish Democrats, such as former Congressman Max Rose, are standing in New York but, in what is expected to be a good year for Republicans, few are expected to ultimately triumph in the November mid-term general election).

“When I was in Congress, you could have a minyan in the New York delegation,” Steve Israel, a former Democrat congressman who represented parts of the city, told the New York Times last month. “We went from a minyan to a minority to hardly anybody.”

The electoral rumble stems from a botched redistricting process which eventually saw the courts step in and appoint an independent expert to draw new boundaries across New York state. The city itself has seen a game of musical chairs as incumbent Democrats seek to cling on to as much of their existing districts as possible and maximise their chances of re-election.

But Mr Nadler and Ms Maloney are the only sitting members to have ended up facing off against one another. Both first elected in 1992, the pair have represented neighbouring districts for the past 30 years. Mr Nadler’s seat – New York’s 10th district – contains the Upper West Side, parts of lower Manhattan and some of Brooklyn. Ms Maloney’s constituency – New York’s 12th district – encompasses the Upper East Side, parts of Brooklyn and Queens. The new 12th district they’re fighting over contains roughly 60 percent of Ms Maloney’s old seat; crucially, however, Mr Nadler’s political base – the Upper West Side – has been added to it. The rejig means that, for the first time in a century, the Upper West Side and Upper East Side will form part of the same district.

Experts believe Mr Nadler would easily have won the new 10th district but couldn’t stomach losing the Upper West Side. The congressman says he’s insisted all along he wants to represent the district he lives in (which now falls in the 12th district). He has also complained that the new boundaries have split two parts of the Jewish community he once represented – Brooklyn’s conservative Orthodox Jews and Manhattan’s more liberal Jews.

Although not especially close, Mr Nadler and Ms Maloney have rubbed along for the past three decades. Both have previously endorsed the other for re-election and there’s been little rivalry over seniority. Mr Nadler now chairs the Judiciary Committee – a perch from which he played a central role in hearings surrounding Donald Trump’s impeachment – while Ms Maloney chairs the Oversight and Reform Committee.

But while the pair were polite and respectful towards one another in the first TV debate earlier this month, the contest has turned into what the New York Post termed “a cage match” with many in the party attempting to steer well clear of the bust-up.

Ms Maloney has thrown most of the punches. She has accused Mr Nadler of failing to tell her in advance he planned to contest “her” district and of sexism because, she alleges, he asked her to stand aside and contest another district. Playing on the perception that she is the more energetic of the pair, Ms Maloney has also suggested that the main difference between the two candidates is “I get things done”.

But, perhaps more contentiously, Ms Maloney has also charged Mr Nadler with using his Jewish faith as a “divisive tactic” in the election. “It’s a strange way to run, it’s sort of like, ‘Vote for me, I’m the only woman, or I’m the only white person, I’m the only Black person,’” she told the New York Times. “Why don’t you put forward your statement, your issues, what you’ve done and the merit you bring to the race?”

Mr Nadler’s remarks on the topic have hardly been incendiary. “It would be very unfortunate if there was no Jewish representation from New York. As it would if there was no Latino representation or no Black representation,” he said last month. His campaign has also sent a fundraising email urging supporters to chip into back the city’s last remaining Jewish member of Congress, describing him as “a person who lives and breathes Tikkun Olam”.

Ms Maloney hasn’t shied away from advertising her own close relationship with the Jewish community, touting an endorsement from the late Eli Wiesel’s son, Elisha, and recent legislation, for which she secured bipartisan support, expanding Holocaust education in schools.

In reality, there are few ideological differences between the two Democrats. “They are old school New York City liberals, one from the West Side, one from the East Side. But there’s no visible or discernible policy differences between them,” Democratic consultant Jon Reinish suggests.

While both are strong supporters of Israel, opposing BDS and attempts to condition military aid to the Jewish state, Ms Maloney has generally taken a more hawkish stance than Mr Nadler on regional issues. Unlike the congressman, she voted for the post-9/11 Patriot Act and the Iraq war in 2003, while opposing the 2015 Iran nuclear deal. The New York Times cited those votes in its endorsement of Mr Nadler last week. The Pro-Israel America lobby group, which has close ties to AIPAC, is backing Ms Maloney, while J Street, a left-leaning pro-Israel group, has thrown its weight behind Mr Nadler.

The congressman has sought to utilise these issues to differentiate himself from Ms Maloney and to appeal to the Democratic base who will decide what’s expected to be a low-turnout race. “She has been wrong on very major issues,” Mr Nadler suggested. “The Iraq vote showed poor judgment. She believed the Bush administration, and I thought the Bush-administration evidence was just not there. The Patriot Act, that was a cowardly vote … it was cowardly on Carolyn’s part.”

While the latest polls put Mr Nadler nine points ahead, the unpredictability of the outcome of the race has led to some hedging by lobby groups – such as AIPAC, the Jewish Democratic Council of America, Planned Parenthood and the National Abortion Rights League – and local politicians who have chosen to endorse both candidates. Mr Nadler’s campaign was boosted, though, when Senator Chuck Schumer, the Senate Majority leader and the most senior Jewish politician in Washington, became the only member of the New York congressional delegation to weigh into the race, offering his long-time ally and colleague a late public endorsement.

Mr Nadler’s supporters point to the fact that he’s been comfortably re-elected 15 times since 1992, has never faced a serious challenge and only once seen his share of the vote fall below 75 percent. In 2020, Ms Maloney, by contrast, came within a whisker of losing the Democrat primary to Suraj Patel, a young lawyer, businessman and alumni of the Obama White House who had run against her in the previous election cycle and positioned himself to her left. That close call, however, may work to Ms Maloney’s advantage; Mr Nadler has not fought a competitive election since before he entered the House. One of the richest members of Congress, who lent her campaign $900,000 earlier this year, Ms Maloney also has deep pockets to draw on and is set to outspend Mr Nadler. He has attempted to turn this to his advantage, noting: “I’m the son of a chicken farmer – no fortune over here!”

Having decided on another attempt to knock-off Ms Maloney, Mr Patel now finds himself embroiled in a three-horse race. While attempting to tap into Democrats’ frustration about a series of conservative judicial wins, he’s largely avoiding drawing sharp ideological divides and instead speaks of the need for “a new generation of leaders”.

But the election isn’t just about generational change, it also reflects demographic changes in the city. The number of Jews in New York has nearly halved – now making up about 12 percent of the city’s population – since the 1950s. As Hank Sheinkopf, a Democratic political consultant and an Orthodox rabbi told the Washington Post: “This city’s more African, more Caribbean, more Asian, more South American, more Mexican, more East Asian …The history of urban politics is always about change and competition among groups and Jews are in the process of losing the competition in New York.” Indeed, Black, Latino and Asian members now make up a majority of the city’s representatives in the House.

But whether Mr Nadler or Ms Maloney are victorious, the Democrats will have scored a spectacular own goal. Two popular, respected members of Congress who hold senior positions in the House have gone head-to-head in an unnecessary and unedifying spectacle. And only one of them is going back Washington next January.