Gerry Adams had no greater friend in Congress than Donald Payne Snr.
He introduced Congressional Bills calling for inquiries into the murders of Pat Finucane and Rosemary Nelson; he turned up at Sinn Fein fundraisers; he had the most pro-Irish (read pro-Sinn Fein) record in Congress; he travelled to Northern Ireland to monitor the Orange marches on the Garvaghy Road, which he loudly condemned. He even delivered a guest lecture in Belfast in which he warmly congratulated Adams on bringing peace to Ireland.
The only problem for Gerry is that Donald Payne was black and proud of it. He was the first African-American member of Congress for New Jersey and he was a member of the black caucus in Congress.
He passed away in 2012 and his seat was filled by his son, Donald Payne Jnr, who, like other members of the Congressional black caucus, will be less inviting to the Sinn Fein president following his description of himself on Twitter as a "Ballymurphy n*****" after watching anti-slavery film Django Unchained.
Sinn Fein, and more specifically Sinn Fein's US fundraising wing, Friends of Sinn Fein, has already relied on African-Americans to come to its events, mostly through Congressmen like Donald Payne, and through black union officials who attend Sinn Fein events.
It's impossible to explain the importance of unions to Sinn Fein's US operation until you are in the thick of it, surrounded by black women offering you cups of tea. I attended one such event, organised by the Transport Workers Union Local 100 in New York, which was to celebrate Adams in the middle of the controversy about the IRA killing of Belfast man Robert McCartney.
Gerry came into the room, led by a pipe band playing The Minstrel Boy and The Wearing Of The Green. Local 100 president Roger Toussaint, a Caribbean immigrant, spoke about the struggle to overcome British colonial oppression shared by the Irish and Caribbean people.
Toussaint wished Gerry well in his continued struggle against foreign occupation. Both the black women in the room and the Shinners loved it. In his speech Gerry spoke about how the founder of the union, Michael J Quill, a former IRA man, had helped both Irish and black workers.
Artfully, he linked British oppression to black people and to the people of west Belfast, ending with the Bobby Sands quote, aimed at impressing the downtrodden blacks as much as the Irish-Americans: "Our revenge will be the laughter of our children."
As he was getting down from the stage everyone was on their feet cheering. The black women were waving their hands in the air, as if they had received the spirit at a gospel revival. I spoke to Darlyne Lawson, an African-American Local 100 union employee, who loved every word.
"For a mother like me, the bit about the laughter of the children was beautiful," she said.
She had not heard about the killing of Robert McCartney, and said she believed Adams was an honest politician and can overcome his difficulties, and indeed he has.
This time, things are different. In the racially-charged environment of American politics, where every word is analysed for signs of racial bias, Gerry's clumsy and shocking use of the n-word will be very badly received by the Congressmen and blue collar unions from which he has received so much support.
Having attended so many of these events, I know what Gerry was thinking. He is used to pulling the "our shared oppression" line with American black people and they genuinely love it. By now he actually believes it and, as a "Ballymurphy n*****", he genuinely thought it was just another step on Sinn Fein's unstoppable foray for the hearts of black people.
Already his comments are being tweeted all over America with great glee by white racist groups.
The laughter of our children may be our revenge, but the next time Gerry returns to New York to express his common oppression with black people, the only one laughing may be him.
The big question hanging over Gerry Adams is whether he believes that the experience of life in Ballymurphy was comparable to the suffering of African American slaves - or whether he has just over-reached himself in familiar propaganda.
Gerry Adams is many things, not all of them savoury, but a racist surely isn't one of them. So on hearing that the Sinn Fein leader used the most inflammatory racist epithet of them all on Twitter when describing himself as a "Ballymurphy n*****!", the charitable reaction would be to shrug it off as yet another social media storm prompted by someone famous carelessly saying something silly that they probably didn't mean, or which was taken out of context, or was simply expressed clumsily.
I was asked by this newspaper if I would write some thoughts on Gerry Adams and the tweet he posted containing the n-word while watching the controversial movie Django Unchained. I agreed.