Sen. Tom Harkin (D-Iowa) has been a key advocate for the health reform law’s Prevention and Public Health Fund. (Alex Wong/Getty Images)

Could other health reform programs follow in its path? While health-care act repeal remains an uphill battle, the deficit debate has made some provisions particularly vulnerable to major budget cuts. In that context, keep a particularly close eye on one particular program: the Prevention and Public Health Fund.

Republicans have regularly attacked the $16 billion investment in programs meant to reduce chronic diseases and improve Americans’ health. Wyoming Sen. Mike Enzi has quipped that the program was a “slush fund” for jungle gyms. To its supporters, the Prevention Fund is huge: its a unprecedented, federal commitment to public health spending that has already sent hundreds of millions of dollars into American communities.

“There’s certainly concern among the public health advocates,” says Jeff Levi, who chairs the new National Advisory Group on Prevention, Health Promotion and Integrative and Public Health “The concern is will it fall into a catch all category of things that can be cut, and that’s a challenge.”

In budget negotiations, the Prevention Fund has faced increased threats. The White House proposed slashing its budget for the first time in its last deficit reduction proposal. House Republicans, meanwhile, would like to zero out the program’s funding in their budget. As Kaiser Health News’ Marilyn Werber Serafini and Mary Agnes Carey pointed out Sunday in The Washington Post, the fund is not shielded from supercommittee cuts, as Medicare and Medicaid largely are.

Prevention Fund advocates see the program as a sort of “make or break” moment for federal prevention funding. It’s such a big investment, they say, that it has to show results. There’s concern that if it gets implemented too slowly, or doesn’t invest in the right programs, the results won’t come through, and public health will suffer a huge setback.

“The question is: are we funding the status quo, are we funding the stagnant quo, or are we getting an effort...that’s transformative?,” Maryland Sen. Barbara Mikulski vented at a Senate hearing on the fund last week. Of all the Congressional hearings I’ve attended on the health reform law, it was by far the most aggressive I’ve seen Democrats get in questioning the administration on implementation.

“We’ve got to get this going. There’s doubt; people think this is a slush fund. The President himself wanted to cut it. We’ve got this window, we’ve got to show movement and momentum...otherwise we’re going to lose the opportunity,” Mikulski said.

“When I hear from OMB, their suggestions for cutting this, that doesn’t sit very well for us who wanted to see this as transformative,” Sen. Tom Harkin, the driving force behind the Fund, added. “We get a little frustrated.”

Outside the Senate, others echo those concerns. “Here’s my concern: we get five years down the road, and we haven’t transformed the prevention system,” says Ken Thorpe, an Emory University professor and former Clinton. health policy advisor. He’s nervous that it could end up a “scatter shot of one program in this community, another in the other community.”

So far, much of the Prevention Fund’s grants have gone to community-wide public health interventions, aimed at reducing obesity and smoking. Most of these grants have been awarded on timelines that span over a few years, which means we won’t have data on results until later down the line. Other grants have gone to increase residency slots for primary care doctors and improving public health infrastructure.

As Ezra pointed out on the blog yesterday, prevention programs can do big things if they’re implemented aggressively; Cleveland Clinic has reduced smoking among its employees from 15.4 percent to 6.8 percent since 2005. Less invasive reforms can work too, but often take longer to show results. Public health interventions have reduced smoking rates, for example: but they’ve done it over a period of decades, and still have 46 million smokers left to go.

It’s an uncomfortable tension for the Prevention Fund, caught between a political process that demands short-term outcomes and public health programs that run on long-term strategies. And it’s one that makes the program particularly vulnerable as lawmakers look for ways to cut spending.