In the wake of the globe-spanning, ground-rattling Live 8 concerts designed to draw attention to global poverty, humanitarian activists now are urging Congress to help fulfill President Bush’s promises about boosting funding to the developing world.

To make their case, aid groups will rely on a combination of Hollywood star power and the surprising grassroots lobbying strength those stars helped assemble in the past few months.

Activists and sympathetic lawmakers acknowledge that the odds are long: In a tight budget year, with lawmakers facing tough decisions about where to cut domestic programs, requests for humanitarian aid often slip to the bottom of the list.

But this year, aid boosters have some new weapons in their lobbying arsenal.

Thanks to the sleek ONE campaign, whose black-and-white television ads featured a parade of entertainment industry A-listers pleading for support, a coalition of humanitarian groups have recruited 1.5 million backers since the effort’s May launch.

Those ranks proved their commitment by sending the White House more than a half-million letters before the summit, asking Bush to hike aid to Africa. Now, ONE organizers said they will tap their network to direct efforts at Congress as Members finalize spending bills.

“Until now, we were almost singularly focused on the G-8 summit,” said Tom Hart, top lobbyist for Debt AIDS Trade Africa, a group co-founded by U2’s Bono and directing ONE’s Washington, D.C., efforts. “We’ll continue to focus our broad attention on awareness, but for many partners in the campaign, the bench mark for success is going to be appropriations.”

ONE draws its name from its goal of devoting an additional 1 percent of the federal budget, or about $25 billion, to aid the world’s poorest countries. That would roughly double current spending levels and may be years off, if it happens at all. So this year, organizers are aiming for Congress to meet spending levels proposed by the White House.

The president’s budget calls for $22.8 billion for foreign operations. The House already trimmed the request to $20.3 billion in approving its spending bill. The Senate version, not yet passed, comes close to the administration figure, calling for $22.1 billion for foreign operations.

While the Senate measure boosts the president’s request in two categories, it cuts funding to the Millennium Challenge Account, a new type of aid Bush launched in 2002 for countries with demonstrably responsible leadership. Activists said they will push to restore funding for that program.

“It’s going to be tall order,” said Jim McDonald, vice president of policy and programs at Bread for the World, a Christian anti-poverty group participating in the campaign.

In the activists favor, no one in Congress is about to argue against ending hunger and disease. The cause has bipartisan support; the challenge is finding enough of it.

“It’s about making this a priority,” said Rep. Betty McCollum (D-Minn.), sponsor of a House resolution that reaffirms Congressional commitment to aid the developing world. “We can spend millions of dollars on defense, or we can spend millions to save lives now, so the next generation [of Americans] doesn’t have to spend millions to defend themselves.”

The ONE campaign includes more than 50 groups, which among them have several dozen registered lobbyists. But organizers also are aiming to make the most of their e-mail lists.

“We’re essentially converting these people into activists for the things they already believe in,” McDonald said. “The ONE campaign is not about screaming monkeys. We want to be a roaring lion. We want this to be an effective voice that people will listen to because it’s powerful and its informed.”

That means making sure the newly minted grassroots force connects with the right lawmakers at critical moments.

To put a face on the e-mail campaign, organizers will look to the Hollywood celebrities who already lent their likenesses to the ads. If the televised spots are any indication, the list of potential celebrity lobbyists includes such high-megawatt stars as Brad Pitt, Cameron Diaz, P. Diddy, Penelope Cruz, Justin Timberlake, Kate Bosworth, George Clooney and, of course, Bono.

While some in Washington scoff at movie stars’ attempts to weigh in on policy as half-hearted and ill-informed, Rep. Jim Leach (R-Iowa.) said they can be effective advocates.

“I don’t underestimate the power of collateral leadership,” said Leach, a co-sponsor of McCollum’s resolution. “And I happen to be a great fan of Bono.”

DATA’s Hart also touted the lobbying skills of the Irish rocker, who in recent years has remade himself into the world’s most visible advocate for debt relief to developing countries.

“He’s got multi-year relationships with Members and the White House on these issues,” Hart said. “Potentially, many other celebrities could be equally effective.”

Organizers said while they have just begun discussions about how to put together their lobbying campaign, it likely won’t begin in earnest until September, when Congress reconvenes and reconciles spending measures.

Likewise, they are holding close the names of potential Hollywood envoys, pending scheduling changes that could shake up their plans.