Do some U.S. efforts to rebuild Afghanistan do more harm than good?

The legacy of U.S. forces in Afghanistan will be debated for years to come, but one of the overlooked elements of America's more than decade-long presence on the country is the effort to rebuild some of the elements of Afghan society that have been destroyed by war - schools, bridges, and hospitals, to name a few. Hundreds of millions of dollars have been spent on these programs, but are they effective?

After the Taliban threatened to attack a medical clinic in Nangarhar province in eastern Afghanistan, U.S. army engineers decided to protect it with a wall.

To help the community even more, the American provincial reconstruction team -- or PRT -- used local builders, but that decision has caused its own problems. The wall is already falling apart.

"They're using bad bricks and bad mortar construction-wise, so we haven't seen the progress that we'd like," Lt. Col. Grant Hargrove said.

Hargrove is trying to build a normal life for Afghans. But you see in his work why America's strategy here takes so long. When we visited the U.S.-built clinic, there were no patients. The doors were locked.

What 100 troops can build can be rendered useless by a whisper.

"They're in an environment that's not really conductive to practicing good medicine all the time, and that makes it challenging," Maj. Robert Niewoonder said.

Niewoonder -- an Army medical officer -- told us insurgents threatened the Afghan staff. "I was told the physician quit, a midwife quit, and the manager quit," he said.

Now Niewoonder is training the local pharmacist to take over.

The PRT team here in Nangarhar started work on this project a few months ago. But the security situation has gotten so bad recently, it may have to be shut down.

Better that, said Hargrove, than spending more money on a project that causes more problems than it solves.

"The bottom line is you have to be very careful how you push reconstruction funding in an area like Iraq and Afghanistan," Hargrove said. "It can actually have a destabilizing effect because you're creating haves and have-nots. You have to look at the tribes and the social dynamics ... and make sure that that spending isn't inciting more violence."

Hargrove said competition for new schools and roads has led to rivalries between villages. A new bridge has drawn Taliban threats. But as Hargrove sees it, there's an even bigger potential problem.

"If the Taliban were to resurge and you lose security, it doesn't matter how much infrastructure you have here. All of that's going to fall apart, and if Nangarhar goes, so goes Afghanistan."

It's a terrible fate for a program built on hope -- projects intended to help the local population are often the first targets for the Taliban.