At the fringes of the anti-G8 trade union rally outside Belfast City Hall there were reminders of those old, ancestral quarrels left behind after the departure of the Obamas and the presidents and premiers who said such kind, effusive things about Northern Ireland.
On one side of the riot police to the right of the unions' platform were the diehard loyalists, who gather every Saturday lunchtime, rain, hail, snow, shine, or socialists, to protest against the flag-change policy of Belfast City Council.
Irony-deficient, they held their latest demonstration to coincide with the larger Irish Congress of Trade Union's march on one of the 18 designated days, when the Union flag does fly atop Belfast City Hall to mark the Queen's official birthday.
Important global issues like the Syrian civil war, world poverty and corporate tax-avoidance all became submerged by 'dreary steeples' subjects, like flags, the mention of the word "Ireland" from one of the Ictu speakers and a somewhat hysterical, ill-informed catch-all denunciation of Israel.
The loyalists, hemmed up against the City Hall railings, booed and jeered at each of these 'heresies'. Everything, in their mind, had to be refracted through the prism of the Ulster conflict, rather than any wider, internationalist perspective.
Similarly, there were those at the edges of the march who also came along with reminders of more parochial concerns. One of them was an old acquaintance from north Belfast, who wanted to convey a message about the apparent power-shifts going on in several republican areas of the city, principally Ardoyne.
He emphasised the point that some nationalist residents no longer bought into Sinn Fein's narrative and took a more jaundiced, radicalised view of moves to reach accommodation over contentious marches with the loyal orders.
This source, whom I trust as a gauge of opinion on the ground, claimed that, among young people, things were starting to slip for Sinn Fein in these areas; that the party no longer led everyone in a common position – especially regarding controversial loyalist parades.
Sinn Fein, to some young people, he contended, were now seen as the establishment, walking hand-in-hand with the Democratic Unionists; determined at all costs to maintain the power-sharing Executive.
Of course, it is important to put what my contact said in context. Sinn Fein is still the biggest nationalist party in north Belfast and commands widespread support throughout the city from the Catholic population. Election after election underlines this political reality.
However, the party is all-too-aware of the dangers of neglecting its once-hardcore base. As Sinn Fein has expanded into the growing urban Catholic middle class, it has to be mindful of its working-class roots.
In districts such as Carrick Hill, the party no longer has monopoly control over all those residents opposed to the Orange Order and their accompanying loyalist bands passing by the newest parade flashpoint – Donegall Street and St Patrick's church.
Standing outside the historic Belfast church last year, there was visible frostiness – to say the least – between senior Sinn Fein personnel and some protest organisers, some of them former comrades; in Ardoyne, the enmity is sharper and even more defined.
Perhaps this explains partly how we have arrived at a situation where Martin McGuinness stands shoulder-to-shoulder with Peter Robinson as they greet President Obama on Monday and, in less than five days, Gerry Kelly is in front of a PSNI Land Rover, appearing to try to stop a police arrest operation during last Friday's Tour of the North parade.
These polar opposite images point to one of the important contradictions of the political settlement.
McGuinness needs to reach out to unionists on a daily basis, to transmit a message across the planet that he and Robinson are an unbreakable double-act, whom dissident republican bombs and violent loyalist flag-linked street disorder cannot decouple.
Conversely, Kelly has to be seen to be on the ground, portraying himself still as a peacemaker who could turn into a street-fighting man of old if the forces of state start to behave in an equally old-style oppressive manner.
Regardless of who started it, the events last Friday night and its toxic fallout illuminates a fault-line just below the surface of the power-sharing edifice.
The two major parties in government are disabled with permanent cricks in their necks because they are forever glancing over both shoulders.
For Robinson and the DUP, their neck-strain is caused by looking right to the alienated, loyalist working class, especially its youth, who form the frontline of the flag protest, and to the left towards that historically important segment of the Catholic middle class who are nationalist in culture, but pro-Union in terms of pragmatic politics.
For McGuinness, Kelly and Sinn Fein, heads are constantly twitching in opposite directions: back left towards those fired up over loyalist marches and further right, to that section of soft unionism that the party dreams might one day be persuaded into the benefits of a united Ireland, or at least in the medium term, of the necessity to keep power-sharing afloat.