Take out your cell phones, the riff continues; make this place into a Christmas tree.

With that, the lights go out, leaving darkness punctuated by the fairy lights of 10,000 waving gadgets. "There's some light in the world," Bono's voice calls out, proving that rock stars can say ordinary things and yet somehow sound profound. "We are powerful when we work together as one."

One, as it happens, is the name of the multimillion-dollar Africa campaign as well as of a U2 love song. With the lights down, Bono sings while the campaign does its thing on the large screen behind him. An invitation flashes up urging fans to text-message their names to the One campaign's number, and soon a zillion bytes are zinging to a special aerial on the roof, erected by Sun Microsystems. The aerial relays the info to the campaign's database, and a few of the names appear like movie credits on the screen. The fans get text messages right back. Please visit www.one.org. And thank you, from Bono.

Bono is not One's only weapon. A who's who of stars illuminates the campaign's TV commercial, which has been given free airtime by MTV, ABC and Fox because it features the likes of George Clooney and Cameron Diaz.

Among the Hollywood royalty is one incongruous figure: silver-haired televangelist Pat Robertson, he of the Hollywood-equals-cesspool rhetoric. Robertson appears on the One campaign commercial right before Sean "P. Diddy" Combs, the rapper whose main contribution to the world is Bad Boy Entertainment.

Robertson? Ah, this is the political strategy. Past efforts to mobilize Americans behind development issues have aimed for a left-center alliance. The message mavens of One aim instead for a coalition of the flanks: for Bill Moyers liberals and lovers of Christian-contemporary music. Last year a version of this left-right pincer helped get an Africa trade bill through Congress; liberal development types made common cause with churches and the business lobby. Today, One is betting that the televangelist-Bad Boy, sects-and-violence combo can build a permanent big-tent movement: a sort of AARP for Africa.

So the Bush folks are pretty much surrounded. Even though they've already launched two major Africa initiatives — the Millennium Challenge Account aid effort and the president's initiative on HIV — it's a pretty sure bet that, in the run-up to the G-8 summit and the U.N. gathering, the Bush administration will have to do another something. The White House has gotten the message that Britain and other rich countries will be announcing bold pro-Africa initiatives. If the United States aspires to lead the world, it cannot stand there empty-handed.

But the real test will be the initiative's content. An announcement that's mainly smoke and mirrors — for instance, a debt-relief proposal that's paid for out of the financial reserves of the International Monetary Fund and the World Bank — won't be much of a triumph. If on the other hand the administration makes a strong announcement involving real new money, the question will be whether Congress will fund it.

That's the ultimate One challenge. The campaign wants to boost U.S. development spending by 1 percent of the budget, a sum equivalent to around $25 billion a year — enough to bring the American contribution up to European levels as a share of GDP. But when the administration recently proposed a modest $3.3 billion extra for all foreign operations, the House leadership cut the proposal by nearly 80 percent, preferring to protect programs such as ludicrous domestic farm subsidies.

So the One campaigners are off to a good start. But the lobbies on the other side are going to take some beating.