Mary Lou McDonald was admirable in her clarity when she delivered a St Patrick’s day message tweet to the faithful – “unity above all else.”

Mary was amongst friends in New York, where the credulity of the Irish disapora for this guff is matched only by their emotional and intellectual incontinence. Bill De Blasio, the mayor of New York, couldn’t wait to go greener than thou with a declaration that March 17 should be renamed ‘Gerry Adams Day’.

For the families of the 2,056 Northern Irish men, women and children murdered by the republican terrorists he’s worked so hard to reimagine as human rights activists, that’s a kick in the teeth. In a city still raw from the pain of terrorism, you would imagine Mayor De Blasio would be better placed than most to appreciate the burdens these families carry – and mindful not to add to them.

But none of these inconvenient truths were allowed to rain on the Fifth Avenue parade. Here in the Big Apple, “unity above all else” has a happy home for at least a day. The fact that Sinn Féin’s version of unity sits above justice, reconciliation or the demographic and constitutional preferences of a majority of people in the North is of no importance to its American disciples. It’s just too easy to drink the Kool Aid – especially when it’s Green.

Back on planet Earth, a different sort of unity was literally playing out on the grass at Twickenham. Thousands of supporters with British, Irish or no particular affiliation poured over the ditch into England’s rugby citadel to watch the climax of the Six Nations Championship.

Players from both sides of the Irish border put on green jerseys. The team was led by an Ulsterman, Rory Best, and the squad was populated by the best of our players from each of Ireland’s four provinces. There’s no place for political posturing and all the other republican socialist codology here – it’s just eighty minutes of blood, sweat and tears. It’s only sport, but it has more power to project a modern, shared heritage than any amount of mawkish transatlantic agitprop. Oh, and it helped that we beat the breed off you English.

The appropriation of Nationalism by Sinn Féin and the aggressive exclusivity of that brand made it largely impossible for Unionists to explore the Irish dimension of their identity through much of Northern Ireland’s modern Troubles. This is a tragedy. We’re a mongrel people – even Ian Paisley knew it was possible to be both Unionist and Irish with half an eye on perfidious Albion’s tendency to behave like it often wanted to ditch its colonists in favour of a quiet life. Moreover, it’s not terribly easy to recognise that aspect of your heritage when terrorists are trying to murder and bomb you into surrendering your Britishness. That sort of carry on does tend to thicken the soup.

It’s not easy to argue the facts of this complexity with your average Irish-American fed by the likes of Noraid – the US IRA support group – on a diet of sanctimony and spite. My favourite encounter with one such customer happened some years ago in a bar in Boston. He seemed gobsmacked to have come across someone with ‘that swell accent’ who wasn’t a fan of the Armalite/ballot box school of democratic enlightenment. When I was then outed as a coloniser, I felt the need to gently point out that my ancestors had been in the North East of Ireland longer than white people had been in North America. And to observe his forebears didn’t exactly have anything to crow about in their dealings with the indigenous population. Sensing the imminence of physical force Republicanism in lieu of further argument, I made my excuses and left. Even post-9/11 this is still a depressingly possible conversation.

It’s made possible by the presence of revisionist republicans who have convinced a fair swathe of political America that because the IRA were part of the Good Friday solution they were somehow never part of the problem. Indeed, people like New York congressman Peter King – an avowed supporter of the IRA – created much of the environment which inspires unthinking and sentimental support for the mass murderers of civilians. It’s probably no surprise that King reportedly hasn’t been back to Ireland since 9/11. Perhaps the semantic twists required to promote one form of domestic terrorism while condemning another were too great even for him.

It’s also made possible by the absence of any true progressive Unionist voice. Yes there was Ian Paisley junior bending the Donald’s ear in a few smug selfies over the weekend but he doesn’t do much for the credentials of modern Unionism given his family heritage and regular faux pas. It’s important for liberal Unionism to be heard in the US corridors of power because people there need to hear a voice that resonates with the coastal fringes and demolishes the convenient dour intransigence which Sinn Fein cultivates and we all too often obligingly help along. We’re flyover country people by inclination (where do you think the Hillbillies came from?) but we need to project a type of modern, confident Unionism which will resonate with those bits of the American administration still curious about the rest of the world.

The trouble is that this form of pro-British sentiment has no real electoral voice in Northern Ireland at present, so we are saddled with a caricature which the Shinners are content to amplify whatever their hilarious slabber about inclusivity. ‘Unity above all else’ relies on us circling the wagons and turning our face against the world. It permits the denigration of a culture which once gave the world literature, invention and industry and is now diminished to the height of a pile of bonfire pallets. It actively seeks to dehumanise and deligitimise those servants of the state and their families who held the line against terror while at the same time morphing our lethal spasm of inter-Christian slaughter into a republican struggle for civil rights equivalent to that in South Africa with Gerry Adams casting himself as a hibernian Mandela. Let’s be blunt, Mr Adams’ lies are half way around Capitol Hill before Unionism has its boots on.

When Ireland play rugby outside the Republic, the fact that two different traditions are brought together on and off the field is reflected in the anthem, Ireland’s Call. It’s not everyone’s cup of tea but singing it allows a rare and unselfconscious moment of unity for people normally inclined to the tribal. On Saturday, ‘One of us’ became ‘all of us’ for 80 glorious minutes. Mary Lou’s call to arms plays well with the plastic Paddies across the pond but can never succeed unless there is a painful acknowledgement by her party – Unity is not above Unionism. In fact the intriguing and perfectly honourable arguments for a new Ireland require Unionists to be a part of that discourse, if only to legitimise and celebrate their difference. Liberal Unionism will need to be part of that exchange. As an equal partner.

Those painful conversations can’t take place on the international stage. The bright lights and green rivers of a New York St Pats is merely an annual distraction for pressing, unfinished business.  We must look each other in the eye, shoulder to shoulder, in the part of the world we all call home, whatever our politics, wherever we wash up. Where the rugby comes from.