Washington ? Few subjects are addressed more frequently or more eloquently by President Bush than the challenge — and opportunity — of voluntary national service. In the last two State of the Union addresses and in dozens of speeches around the country, this president has urged his fellow Americans to devote time and energy to community projects. And he has pledged his best efforts to expand government programs of national service.

His advocacy seems entirely sincere, which makes it even harder to understand how the main instrument of such service — the AmeriCorps program — may well shrink on Bush’s watch.

On Monday, the AmeriCorps agency is scheduled to make a long-delayed announcement about how many volunteers it will accept this fiscal year to work with local charities and social agencies and, if they wish, gain college scholarship money for themselves.

At best, AmeriCorps will open its doors to 50,000 full- and part-time mentors, organizers and workers — the same number it has now. More likely, the number will shrink to as few as 35,000 — a big step backward.

Rosie Mauk, the AmeriCorps director, told local groups in a memo last week that even under the most hopeful scenario, they should expect “fewer new AmeriCorps positions in 2003 and good programs that received grants in the past will not be funded this year.”

“I have a great concern over the loss of services,” Mauk told me in an interview. “Obviously, this doesn’t meet the president’s goal of expansion.”

AmeriCorps has been struggling with accounting and managerial problems for years. An effort to address some of its difficulties with a new authorization bill foundered last year when Dick Armey, then the House Republican leader, said he would not call up the bill before Election Day.

A number of conservative Republicans — not enough to defeat it but enough to raise a ruckus — have been dead set against what they call “government-financed volunteerism” ever since President Bill Clinton launched AmeriCorps a decade ago. Bush did not lean on Armey to get the reform measure passed.

Still, the program is wildly popular among the local and faith-based agencies who use the AmeriCorps workers to help organize and coordinate local volunteers. Governors and mayors of both parties praise it, as Bush did when he was in Austin.

At his road stops, Bush likes to introduce AmeriCorps workers, while telling audiences that “we’ll increase AmeriCorps by 50 percent.”

That goal was also set forth in the president’s budget for fiscal 2004, which administration documents said would take AmeriCorps up from 50,000 to 75,000 people.

But despite the rhetoric, skeptics noted that Bush actually reduced his request for AmeriCorps grants from $364 million for fiscal 2003 to $324 million for fiscal 2004.

When asked how they expected to grow the program by 50 percent at lower cost, AmeriCorps officials said they have “achieved a lot of efficiencies” and have found that many of the local groups that get AmeriCorps workers are willing to subsidize their living expenses, reducing the cost to the government.

Meantime, the Republican Congress — so responsive to the president on taxes or defense spending — has been surprisingly balky when it comes to this announced domestic priority, a symbol of Bush’s “compassionate conservatism.”

In the delayed spending bill for fiscal 2003, Congress appropriated only $175 million for AmeriCorps grants. It set 50,000 as the cap on the number of volunteers and declined to act on a Bush request in March to remove that ceiling. Congress also pressed the agency to clear up a dispute about how much money must be set aside to finance future education benefits for AmeriCorps volunteers. It is that dispute that has delayed AmeriCorps from deciding how many slots it can actually afford this year.

All this has taken a toll — in the real world, where these volunteers have done so much effective work.

The inexplicable thing is that national service is a concept that commands broad bipartisan support. Sens. John McCain, the Arizona Republican, and Evan Bayh, the Indiana Democrat, have reintroduced their 2002 proposal to build AmeriCorps gradually to 175,000 members. They were joined this time by Sen. Edward Kennedy of Massachusetts.

White House officials insist that the president is lobbying privately as well as talking publicly about expanding the service program. They say that House GOP leaders promised him last week to bring an expanded Citizens Service Act to a vote before the August recess.

Such talk has been heard before, and Bayh is not the only skeptic who worries that the delay means “a real missed opportunity” to convert Americans’ post-9/11 patriotism into action on national service. “It wouldn’t take much political capital to get it done,” Bayh said. “Bush has said all the right things. Now he needs to act.”

— David Broder is a columnist for Washington Post Writers Group.