AmeriCorps backers tried and failed last month to get $100 million from Congress for the financially strapped national service program. Now, they are trying again -- and hoping to build a lasting coalition to avert the next crisis.

More than 50 AmeriCorps-affiliated groups representing thousands of people from across the country are organizing "Voices for AmeriCorps," 100 hours of "testimony" on behalf of the program. The event, to be held in several government office buildings from Tuesday to Saturday, will coincide with the lawmakers' return from their August recess.

The more than 300 speakers will include representatives from the groups, academia and the business world. They will discuss the importance of service, the AmeriCorps programs' successes and the impact if the government does not fully fund 50,000 AmeriCorps slots for 2003.

"We've got to do something dramatic," said Alan Khazei, an event organizer and head of City Year, which recruits 17- to 24-year-olds for a year of community service in urban areas. "There is an incredible faith among the national service community that if our nation's leaders, including the opponents, just got a chance to understand the impact of AmeriCorps at the grass-roots level, that they would support this."

Mismanagement at the Corporation for National and Community Service left the parent agency of AmeriCorps unable to fund as many as 20,000 of 50,000 AmeriCorps slots this year. AmeriCorps advocates argued that local programs should not be punished for the mistakes of bureaucrats. Forty-four governors and more than 200 corporate leaders signed on to their cause.

In July, the Senate approved an emergency infusion of$100 million for AmeriCorps, but House Republicans refused to go along, saying it would be a bad investment. AmeriCorps backers say they will now concentrate their efforts on the legislative branch's appropriations bill.

The impasse is due, in part, to a belief among some in Congress that the government should encourage volunteer efforts -- but not fund them. Doug Bandow, a senior fellow at the libertarian Cato Institute, said such funding could undercut the sense of civic community that AmeriCorps backers say they want to build. Instead of donating to worthy groups, taxpayers would in effect be encouraged to consider community concerns as the government's problem, not theirs, he said.

"You've got a vibrant but relatively small charitable sector there, and now government is coming along and saying, 'Oh, don't you all worry, we will help pay for it and we will hire volunteers for it,' " he said.

AmeriCorps volunteers work 20 to 40 hours a week and provide services such as literacy coaching and cleaning parks. Some volunteers receive modest living stipends, but all are eligible for grants of $4,725 to pay for college or to repay student loans.

President Bush has frequently spoken out in favor of the Clinton-era program and promised to expand it to 75,000 volunteers next year. But he did not intervene with House Republicans to secure the $100 million.

"I wonder why he has not been able to put some of the prestige of that bully pulpit to work behind getting support for something which is so self-evidently useful and good for the society in which he lives," said Robert Burkhardt, head of the Eagle Rock School in Estes Park, Colo., who is scheduled to speak next week. Each year, a dozen AmeriCorps volunteers assist teachers at the 96-student private high school, which enrolls children who have had trouble at their regular campuses.

Administration officials have said Bush remains committed to expanding AmeriCorps.

Khazei said he hopes the new coalition will endure beyond next week's event. The event's $250,000 cost is being underwritten by Atlantic Philanthropies and another foundation Khazei would not name.

Nan Aron, president of the advocacy group Alliance for Justice, which offers workshops on lobbying for other nonprofits, said that the new coalition is significant but that its staying power is uncertain.

"Up until now, many of the organizations have shied away from public advocacy," said Aron, who is not involved in the coalition. "It seems to me that at a time when the president is looking a lot more conservative and a lot less compassionate, this is an opportune moment for these groups to speak out."