In truth, though, the triumph is, at the moment, largely semantic. Yes, everyone attending finally agreed that it was a good idea to offer up to 100 per cent debt relief to some of the poorest countries. But only Japan and Germany had outstanding reservations anyway. What matters next is how quickly and effectively the G7 countries can act on this realisation.
For many of those who have been campaigning for debt cancellation for years, this latest stopping-off point can be considered as just one more delaying tactic - another opportunity for the powerful to bicker over detail while their fellow humans sicken and die.
But, on the other hand, what's the harm in setting aside cynicism and instead marvelling how a policy seen 20 years ago as ludicrously idealistic, naive, happy-clappy and leftie, should have find international establishment favour? Brown is right. This really is a fine thing.
Unfortunately, though, the warm glow of agreement around this single fine thing does not necessarily signal a meeting of minds on any others. In fact, in many respects this latest G7 meeting, so pumped up by Brown for his own political glory, has done nothing more than emphasise how static the differences between the G7 states - and within the Blair government - now appear to be.
One could, for example, hail the support of the European Union for Brown's International Finance Facility - to provide upfront aid by borrowing against future commitments by selling bonds on the capitals market - even though the US rejects it. How refreshing, one might think, to find Europe united once more.
Except that Chirac in France - supported by Germany - has more radical ideas for funding African aid (killing two birds with one stone with an environment-friendly aviation tax), while Blair's office is rumoured to have gone off Brown's complex plans anyway. Despite appearances, none of these powerful people are any more conciliatory than they've been for years. The chances of them agreeing on anything practical still seems remote.
Brown's people insist that the IFF, or something like it, can go ahead without the support of the US. But, in fact, without America's agreement neither Chirac's nor Brown's brainchild, nor anything like it, is ever going to hit its developmental milestones. The problem is not disagreement on detail. It is fundamental.
The US Treasury under-secretary, John Taylor, commented after the meeting: "We focus on the results on the ground rather than fractions of gross domestic product [devoted to aid]. We have never thought that fractions of GDP are a very good way to generate funding for aid. The American people are very generous. We feel as if we have a good way to provide assistance the way we are doing now."
What he really means is that the US intends to continue to target its government aid at areas where it has a geo-political influence or where there is some sort of economic payback for the US economy, while pretending that private generosity (which indeed exists but is too often directed at disaster rather than development) comes anywhere close to compensating for a well-funded international development effort.
The grisly, unwanted effects of this sort of controlling and deluded attitude have already come home to roost in America, with fighting its war on terrorism being treated, erroneously, as a far, far greater priority than tackling international inequality.
Tony Blair is of the opinion that the way to persuade the US to join in with tackling global inequality is to persuade it that this is the best way to "drain the swamp" that allows extremism to fester. Yet how alien this pragmatic approach is to US thinking can be confirmed with a glance at yesterday's budget announcements, and the further privation they intend to impose on the most vulnerable of America's own citizens.
In order to pay for tax cuts for the wealthiest one per cent of Americans and to continue to finance the war In Iraq, President Bush proposes cuts in food stamp provision for the poorest Americans, cuts in subsidy for public housing and cuts in programmes aimed at tackling the diseases of poverty. A programme that helps the poor pay heating bills is to be trimmed back by 8 per cent, while the administration also intends to save $60bn (pounds 32bn) over the next decade by cutting Medicaid.
Yet, funnily enough, despite their brutality and their contempt for the underdog, the budget proposals do not bring nothing but bad news for the poorest people in the world. There are also hints that the US government is keen to save money by challenging the US Farm Bill which delivers pounds 190bn in subsidies to American agriculture.
Europe's leaders are fond of gnashing their teeth over the hypocrisy of the US, with American recalcitrance over IFF simply the latest piece of self-serving It's-not-our-fault-we're-doing-our-best propaganda. But the truth is that nothing that is likely to be achieved by Brown's initiative would transform the fortunes of Africa as much as the removal of not just US, but also European farm subsidies.
Rather than continuing with round after round of impossible negotiations, all of which fail to thrive due to the reluctance of America to act multilaterally, isn't it about time for the international community to concede to the idea that it's aims might gain more by identifying areas for reform that are in the US government's interests as well as global equity's.
Agricultural subsidy is one such area. Swingeing welfare reform is not going to lose any votes for Bush. But among conservative farming communities, attacks on subsidy are likely to go down badly. With Bush's budget deficit now running at $400bn a year, it might prove useful for him to be able to present farm subsidy cuts as part of a saintly international effort aimed at defusing the terrorist threat by "draining the swamp".
The harsh truth is that the rest of the world is not hindered by the US in its progressive agenda as much as it likes us to think. Instead, sometimes it hides behind America's stubbornness, heaving a sign of relief when the infantile behemoth makes another tough agenda unsustainable.
This is not to say that there is no political will to make the world fairer and safer. It's just that in democracies, unfortunately, the prospect of winning votes in a few months or years is always more pressing than being around to get the credit because the world hasn't ended.
For Brown and for his party, the idea of debt cancellation - not today but possibly in July, just after the election - is simply perfect. That's not Brown's fault. He's sincere enough in his ambitions. But they're awfully similar to the ambitions others have had before him.