New York - Bitter presidential rivals Hillary Clinton and Donald Trump have one more face-to-face showdown before Election Day. And they're supposed to make it funny.The venue on Thursday night just 24 hours after their third and final debate is the annual Alfred E Smith Memorial Foundation Dinner in New York, a white-tie gala that every four years becomes a showcase for presidential politics. Tradition dictates that the candidates deliver humorous remarks poking fun at each other and themselves, a jovial custom that seems hard to envision amid such an ugly campaign.Trump regularly calls Clinton, "Crooked Hillary", says he'd put her in jail if he wins the presidency, and declared during Wednesday's debate that she was "a nasty woman". Clinton says Trump lives in his own reality, is running a "hateful, divisive campaign" and lacks the temperament to be president.They will sit just one seat apart for the evening, with New York's Cardinal Timothy Dolan acting as the only buffer."I certainly expect that the dinner will be what it's always been: an opportunity for two candidates to put aside partisan politics for the evening," said Joseph Zwilling, the spokesperson for the Archdiocese of New York, which hosts the dinner. "I anticipate that we will have good humour and civility that this dinner has been always been known for."The unprecedentedly bitter campaign between Clinton and Trump could threaten the ecumenical goodwill that has defined previous roasts. Since 1960, at least one of the major party nominees has appeared at nearly every election year dinner, which is traditionally the last time the nominees share a stage before voters go to the polls.Four years ago, President Barack Obama and Mitt Romney set aside their differences to trade (mostly) warm jokes. Romney, scanning the well-heeled crowd in the gilded Waldorf-Astoria ballroom, joked that the event's white-tie attire finally gave him a chance to publicly don what "Ann and I wear around the house". Obama, meanwhile, used his speech that year to look ahead to an upcoming debate on foreign policy, previewing his argument by saying "Spoiler alert: we got bin Laden."Confirmation both will be thereTrump will speak first Thursday night, then Clinton. Neither campaign opted to preview their candidate's remarks and aides for both declined comment on the evening other than to confirm that each nominee will be there.The evening might feel familiar to Trump, who infamously glowered through Obama's jokes at his expense during the 2011 White House Correspondents Dinner and is not known for being self-deprecating. Last weekend, he tweeted that he did not appreciate Saturday Night Live's portrayal of him in a send-up of the candidates' performances in the second presidential debate.This is the first time that both party's nominees hail from New York State as a crowd of about 1 500 gathers for the distinctly Gotham event, held each October. Attendees pay between $3 000 and $15 000 for the dinner, which raises about $5m to provide services for impoverished children, Zwilling said.Though normally light-hearted, hot-button issues - most notably abortion - have occasionally intruded on the night. In 2004, the candidates did not attend after the Catholic Archdiocese of New York agonised over whether Democratic nominee John Kerry, a Catholic who supports abortion rights, should be invited. Abortion rights had been a back-burner issue this election, but Trump and Clinton sparred over it Wednesday.The dinner is named after the former New York governor, who was the first Catholic to receive a major party nomination for president when he unsuccessfully ran in 1928. And fittingly for an event named after a man nicknamed "The Happy Warrior", the occasion has produced dozens of memorable presidential jokes.In 2000, then-Texas Governor George W Bush gazed upon the glitzy gathering and declared: "This is an impressive crowd, the haves and the have-mores. Some people call you the elite. I call you my base."That same year, Vice President Al Gore touted his campaign trail ability to weave in stories "of real people in the audience and their everyday challenges"."Like the woman here tonight whose husband is about to lose his job," Gore continued. "She's struggling to get out of public housing and get a job of her own. Hillary Clinton, I want to fight for you."And in 2008, John McCain joked about the exalted manner in which the media venerated Obama, noting that "'Maverick' I can do, but 'Messiah' is above my pay grade". But he wound down his remarks with a note of grace that, to this point, has been largely absent from the 2016 campaign."I can't wish my opponent luck," McCain said, turning toward Obama, "but I do wish him well."