Donald Trump and Hillary Clinton asked to show 'collegiality and good humour' at annual Catholic dinner

The instructions to the two presidential candidates when they take the top table together at Thursday’s annual Alfred E Smith Dinner in Manhattan will be clear enough: keep it fun, humorous and witty. But this year, even keeping it civil threatens to be a challenge.

No one who has paid the required $3,000 (£2,400) to attend the charity roast at the Waldorf Hotel will be unaware that the two star guests, Donald Trump and Hillary Clinton, are currently engaged in the most uncivil presidential race of modern times.

Named after a former Governor of New York, the dinner is a Catholic charity event to raise money for the city’s poorest children. Every four years it becomes a platform for presidential candidates to show that even days before the election, they can still wash the mud off for an hour or three and make each other laugh with gentle jabbing and large helpings of self-deprecation.

Now in its 71st year, the dinner has long thrived in the finest tradition of the American political roast, where mean fare is fine, so long as it is funny. Bitter is banned, in the cooking and in the remarks. The first Catholic ever to run for president, Governor Smith was known as the ‘Happy Warrior’ for his ability always to keep a sense of humour in the midst of political combat.

“The presidential nominees will share the dais with Timothy Cardinal Dolan, Archbishop of New York,“ the Archdiocese of New York said in a statement. ”And they will deliver the evening's speeches in the spirit of collegiality and good humour that has become a hallmark of the gala.”

Rarely has the potential for the dinner to go horribly wrong been so great, however, as it takes place 24 hours after Ms Clinton and Mr Trump’s final presidential debate in Las Vegas. If their previous encounter is anything to go by, they will fly to New York applying salve to the wounds they will have newly inflicted upon one another.

But organisers are crossing their fingers, and perhaps praying a little, that even these two candidates can find it in themselves to mix some affection into the warfare.

“We’re all craving some level of decency,” Alfred E. Smith Memorial Foundation board member Maureen Sherry told Bloomberg News this week. “Whoever will prevail on that evening will be the one who can take the higher road.”

It has worked in the past. In 2008, when Senator Barack Obama rose to his feet, he pretended to be irked that the event was not in Yankee Stadium and there were no Greek columns in sight – a reference to his acceptance of the Democratic nomination that year that was widely lampooned for its grandiosity.

Looking at his Republican foe, John McCain, he made fun of running mate Sarah Palin, and her claims of having kept an eye on Russia from her Alaska garden, by saying he had gathered that from the front step of the Waldorf “you can see all the way to the Russian Tea Room”.

Of course, self-deprecation from Mr Trump could be especially effective this week because it is not a talent he has often put on display. No one would blame him, meanwhile, were he to get somewhat close to the bone about Ms Clinton and her relations with Catholics.

She is a Methodist. But more importantly, recent WikiLeak documents have shown top Clinton advisers allegedly swapping emails making fun of some prominent Catholics, including Rupert Murdoch, for embracing a faith they “think is the most socially acceptable, politically conservative religion – their rich friends wouldn't understand if they became evangelical”.

How close Ms Clinton will choose to sail with respect to Mr Trump and his alleged abuse of women is a whole other question, meanwhile, that will have some guests nervously jiggering they knees and clinking their forks on the chinaware.

As he surveys the guests in white tie and the gilt of the Waldorf ballroom, Mr Trump might be reminded of another famous regular roast, the annual White House Correspondents’ Dinner in Washington. It was there in 2012 that Mr Obama was merciless in mocking Mr Trump, one of the night’s guests, for attempting to suggest he was not American-born.

“Now, I know that he’s taken some flak lately, but no one is happier, no one is prouder to put this birth certificate matter to rest than The Donald,” Mr Obama riffed. “And that’s because he can finally get back to focusing on the issues that matter – like, did we fake the moon landing? What really happened in Roswell? And where are Biggie and Tupac?”

It was that mockery, with all of Washington watching, that some say convinced Mr Trump to seek the presidency himself these few years later as a form of revenge.