They come in their thousands from the republican heartlands of the Falls Road, Andersonstown, New Lodge, Ardoyne and other Catholic districts to celebrate their Irish identity in what is still essentially a British city.
A few decades ago a St Patrick's Carnival followed by a sea of Tricolours and Republic of Ireland shirts would have been unthinkable in the once unionist-dominated "capital" of the North. Now this loud, out and proud parade of Irishness is an annual fixture in Belfast's cultural calendar.
This year, however, perhaps, those who remain loyal to Britain will have something to celebrate on St Patrick's Day as well. Because it is one of the 17 designated days when the red, white and blue of the Union Jack will fly over Belfast City Hall. In an ironic twist, which might be lost on so many irony-deficient loyalists, Paddy's Day 2013 will be an occasion when the pro-union population can be assured that Northern Ireland is still British if they care to look up to the green-domed roof of the City Hall.
There are four main reasons why the mayhem has erupted over the last four weeks leaving 62 police officers injured, and more than 100 people arrested for rioting offences.
The first of these is a general sense of disconnection from the power-sharing political process at Stormont. Those who support or have given succour in the past to loyalist paramilitary forces, the urban Protestant working class, have no representation of their own in the Northern Ireland Assembly.
Unlike Sinn Fein vis a vis working class Catholics, the loyalists of deprived areas such as the Lower Newtownards Road either don't vote or have little in common with the middle class dominated mainstream unionist parties. One of the reasons why Belfast City Council voted to end the policy of flying the union flag 365 days per year was because the council is finely balanced between unionist and nationalist councillors. Unionism could have had a majority on the council but because the voting turnout in Protestant working class wards is so poor, the last local election returned fewer unionist councillors. In effect loyalists bemoaning the flag policy change have only themselves to blame due to their own apathy.
In addition, many of the young people using football scarves and hoodies to disguise themselves as they bombard police lines have little or no prospect of ever working again, or at least holding down any job for life.
The third factor motivating and exacerbating this crisis is both the role and nature of loyalist paramilitarism. Regarding the latter, loyalism is fragmented and federal unlike say the IRA. So, while the Ulster Volunteer Force's central command on Belfast's Shankill Road is known to be, at the very least, lukewarm about these flag protests, its so called East Belfast Battalion is in the vanguard of the disorder. Last Saturday night, for example, while the Lower Newtownards Road in the east of the city resembled a battleground with shots being fired at police and petrol bombs being met with plastic bullets, the Shankill Road, loyalism's historic urban heartland, was peaceful with parents out walking with their children and locals enjoying a smoke outside some of the pubs along the famous thoroughfare.
The East Belfast UVF, who the North's Chief Constable Matt Baggott accused of orchestrating much of the last six days of violence, has its own specific agenda in fomenting trouble. Its leaders' ill-gotten assets, including pubs they own, have been targeted by the UK Serious Crime Agency while a number of key figures in the area are under investigation for past crimes. By lending muscle to a protest movement sparked by the flag policy change they can remind the authorities of their ability to destabilise Northern Ireland, their aim being to 'blackmail' the state to get off their backs.
The 'footsoldiers' of this war, some of them as young as 10 or 11, will not be aware that they are mere pawns in a cynical game of extracting concessions from the state. Many of these young rioters also have some of the lowest educational attainment anywhere in these islands and are extremely vulnerable to manipulation especially from those who tell them they're on the slippery slope to a United Ireland.
It is a nonsense to suggest that the flag change policy substantially impacts on Northern Ireland's continued link to Britain. Even the hoodie-rioters only have to reach into the pockets of their tracksuit bottoms and pull out a pound coin, examine the back and spot that the figurehead on the currency remains a woman with a crown on her head.
Henry McDonald is Ireland Correspondent for 'The Guardian' and 'The Observer', and co-author of 'UVF–The Endgame' and 'UDA – Inside the Heart of Loyalist Terror'.