Images of Belfast's brick-hurling thugs seem like unwelcome eruptions of ancient history on American internet feeds. Rooted in England's very first colonial venture under Henry II in the 1100s, the continuing argument over Northern Ireland is both impenetrable to outsiders and embarrassing to most natives.
Even writing about Northern Ireland is filled with roadblocks. It's Protestants vs Catholics, except faith is really beside the point; loyalists vs republicans, though most Northern Irish identify as neither and want nothing to do with violence; or unionists vs nationalists, except a growing number of Catholics support remaining with the United Kingdom and thousands of Protestants have voted with their feet by leaving the island.
Some dispute that the English colonised Ireland at all, since Henry's troops were actually invited in by a desperate Irish nobleman, who then watched the monarch swallow the island whole. Why haven't these people gotten over it yet, Americans might ask. And why exactly should we care?
A Chicago native with Ulster roots, I've watched for years as the Journeyman Plumbers dump coloured powder into the Chicago River on St Patrick's Day, dying the murky water a virulent green.
Billed as a spectator-friendly celebration, in fact it's a Catholic/nationalist/republican insult to any member of the Protestant/unionist/loyalist faithful, who call themselves Orangemen after King William of Orange (another acquisitive European monarch).
The quick answer is that the past always matters, everywhere. On the streets of Belfast, the Northern Irish are giving Americans a masterclass in its potency.
What is less heralded is that in this tiny, lovely corner of the old sod, people are also acknowledging the past and finding creative, effective ways to drain it of hatred.
Maybe it doesn't look that way in July and August – the so-called 'marching season' – but for most of the year, there's a lesson here that Americans would do well to learn. In North Carolina, where I live, the governor just signed a voter ID law that reads like a primer on how to disenfranchise African Americans and the poor, Jim Crow-style.
When I protested the bill (and was arrested) at the state legislature in June, accompanying me was 92-year-old Rosenell Eaton, an African-American woman who, unlike any whites, had to recite the preamble to the US constitution perfectly just in order to vote.
Yet white America, in particular, denies, or just doesn't see, that racism is alive and even thriving.
I've been bringing Duke University students to Northern Ireland since 2009. The students volunteer with groups working toward peace. In the city, the walls between communities are concrete and chain-link, not lodged in the colour of our skins, as they are Stateside.
More than 90% of Northern Irish schoolchildren aged four to 16 still attend segregated schools. Most people live in self-segregated neighbourhoods, mixing only downtown, or when an international act books in at the Odyssey. Even favoured vacation spots in Spain and Portugal are divided up by tribe.
So what, exactly, could the Northern Irish possibly be doing right? Most importantly, not a soul on the island denies that history shapes the present and matters.
History matters a lot. People talk about history constantly. Institutions like the Churches, the Government and international funders engage in and support efforts to bridge communities divided by the past.
People marry across the divide, work in mixed offices, club in mixed groups and play on mixed teams. At the nursery gate, birthday parties and graduations, formerly warring tribes find new bonds that build on, but aren't split by, the past.
For the first time this summer, Northern Ireland's leaders proposed a plan to disassemble so-called 'peace walls', erected to dampen cross-community attacks. The plan remains aspirational, but it's something everyone discusses – a healthy sign.
Amnesty International recently released a report showing how much work needs still to be done. Yet there are people and groups who have already dedicated themselves to this necessary work – a positive sign.
Discussion, in the end, is the first step to addressing the past. But to discuss, you have to first admit that there is a problem. That's where Americans fail.
President Obama doesn't support a White House forum to discuss our history of racism, and I agree. These sorts of discussions work best closer to home, when people know each other as neighbours and colleagues.
Instead, the president should propose a plan to encourage American cities and towns to hold their own forums, with the power to take action, whether it is to devise ways to address racism, recognise forgotten heroes, or simply come together to celebrate.
Whites who don't see a problem need to step back and listen hard. Blacks who claim nothing has changed need to review. No-one is exempt from the past; but no-one is its prisoner, either.
One of my favourite murals in Belfast is topped by a version of a Winston Churchill quote: "History is written by the winners." The truth is that each generation writes its own histories.
In Northern Ireland, people want their histories to lead toward peace and coexistence, in whatever form. In spite of the intermittent thuggery, they are winning.
Americans would do well to ask the same of their own stories.
Dr Robin Kirk is associate director of the International Comparative Studies program at Duke University, Raleigh-Durham, North Carolina