Protests against the G8 will not have achieved very much. We live in a part of the world in which protest simply doesn't work any more, or at least does no more than advertise a grievance. It doesn't change the plans of governments.
And as a political strategy with so little going for it, protests that end peacefully are at least better than those that turn violent in that nobody gets hurt.
Had there been a clash with the police in Belfast on Saturday the repercussions would have been difficult to manage.
A massive police turnout to manage a couple of thousand G8 protesters would have contrasted sharply with the treatment of flags protesters over the last six months. And with so many of the police personnel on the ground being from English forces, the potential for embarrassment was mighty.
For what both the protesters and the police knew was that the local political context was irrelevant.
The tender-handed policing of flags protests and the concern to avoid irritating a local mix of passions would have had no part in the response should trouble have erupted.
That was the message of the huge police presence and the standby water cannons. The peelers were up for a ruck. And one wonders who in the planning of this was advising that the negative impact of, say, a mass kettling or a few cracked skulls would have damaged local relations with the PSNI, which are still ambiguous but vital.
Security over the G8 will not be constrained by the local custom of going easy on violent political expression; it will not be tailored to the needs of a peace process. What we saw in Belfast on Saturday was that the resources were put in place to manage a G8 process in just the way they do it elsewhere. And one of the places which provides a worrying example of a policing culture in which protest is crushed is London.
That is where they invented the strategy of surrounding protesters and penning them in for hours, presumably until many had wet themselves.
And that is where the protesters have developed tactics like fragmenting the main body and scattering in different directions, refusing to be corralled and stretching security resources.
That is a game we were better not learning.
Yet protest culture is alive and strong and even growing in other parts of the world. Some of it is religious, jihadist and has attracted support from British and Irish Muslims. Some from here even went out to fight with revolutionary armies in Libya and Syria.
In Turkey, a secular revolution pitted against a religious-minded government appears to be attracting some Westerners.
The ferment in the Middle East will be part of the discussion over the next two days by the G8 leaders, confronted by the threat of an enormous war engulfing the region and becoming a proxy for war between Russia and the US, 25 years after the Iron Curtain came down.
The stakes may never have been higher in the lifetime of any of these leaders. President Obama is ready to play some kind of hand against the winning alliance of Iran, Syria and Hezbollah, backed by Russian arms, which must sooner or later threaten Lebanon and Israel.
David Cameron, faced with the clear failure of austerity measures to revive the economy, may at last have realised that there are some evils in global capitalism, like the eagerness with which big business spirits its earnings into tax havens and leaves the funding of states to the workers, who earn as little as the same companies can get away with paying them.
But we have heard ambitious plans for remaking the world in a more benign image from G8s before. They met in Gleneagles to end world poverty.
Maybe next time they will be offering tax breaks for tooth fairies.
Street protest will not change the plans of heads of state but it at least puts on the historic record that some here were concerned about the world beyond their own streets.
To judge by much of the media you would think that Barack Obama was here as a motivational speaker, even some kind of spiritual inspiration. What he will do, which is important, is meet with Vladimir Putin, a warrior leader of Russia, who was not squeamish about destroying Chechnya and Georgia, and he will have to look him in the eye and measure his response in a massive deadly chess game he is playing against him in the Middle East.
And to listen to some in the media you would think that this was all about little more than attracting tourism to Northern Ireland.
They have high hopes that a few photos over Obama's shoulder of the Titanic Quarter or the Fermanagh Lakes will bring thousands here for their holidays.
Well, they might.
But Obama knows it is bigger than that and so do the protesters.
And if this wartime summit produces a bad result it will be the protesters who will have saved our face and left a reminder that some here knew the scale and the cost of what was left on the table when the cutlery was cleared.