KANDAHAR, Afghanistan — Under a scorching sun, Defense Secretary Bob Gates tells soldiers from the first U.S. combat brigade deployed inside this city that they’re the “forward foxhole” in the fight against the Taliban. It’s already a bloody battle: In its first two weeks here, the brigade has lost eight soldiers, including five killed last Monday in a roadside bombing.

Gates hears an upbeat account from the brigade’s commanders about their patrols alongside the Afghan army and police in this Taliban stronghold. And, after touring several fronts in the make-or-break Kandahar campaign, Gates tells reporters he’s “encouraged” about prospects for stabilizing the area and eventually transferring responsibility for security to the Afghans.

Soldiers gathered in the shade for a smoke offered a more cautious assessment. Sgt. Michael Ellis, who leads the security team for one of the brigade’s commanders, says of the Afghan army and police: “They’re just not up to speed. They lack organization.” He says that when he came under attack with Afghan troops a few days ago, some of them began firing their AK-47s erratically into the sky.

This contrast between commanders’ high hopes for Afghanistan and stubborn realities on the ground is the strongest impression from a visit here last week. Traveling with the military, there’s always something of a contact high — with senior officers assuring visitors that the mission can be achieved. But the Afghan strategy is still very much a work in progress, with many of the key concepts still unproven on the battlefield.

Enthusiasm certainly was the theme of a briefing Gen. David Petraeus gave to reporters traveling with Gates. He stuck to an upbeat script, using slides remade from those he developed during his successful Iraq campaign. Petraeus, who took over command just two months ago, said he is still framing the details of his “commander’s guidance” for this war.

In an interview, Gates offered a more careful analysis than the one he gave in the blazing Kandahar heat. “I think it’s too early to draw any conclusions,” he said. “We need some months more to look at this” before a December review evaluating “proof of concept.”

“If it were to be clear that the strategy is not working, then I would be one of the first to advocate changing the strategy,” Gates told me. “I will not sign the deployment orders sending kids in harm’s way for a strategy that I don’t believe works.”

As Petraeus shapes his battle plans, he is coming at the problem from several directions at once. There’s a top-down component, working with Afghan ministries and the national army and police. But there’s also a bottom-up push, in which U.S. Special Forces will work with tribal leaders to form “local police.”

Gates and Petraeus both played down recent friction with Hamid Karzai over what many Obama administration officials believe is the Afghan president’s erratic leadership. Gates, who thinks Karzai-bashing is a mistake, looked like the Afghan leader’s kindly American uncle at a joint news conference here.

But at the same time it cajoles Karzai, the U.S. is working with many local and district leaders and tribal maliks who oppose him. Much as Petraeus did in Iraq, the U.S. wants to play both sides of the street — working with the government and its “reconcilable” opponents. Gates said the U.S. was “rebalancing” its approach to reflect Afghanistan’s “history and culture where regional, provincial and local authority have always been strong,” and to “re-empower some of the tribal shuras.”

The plan for Kandahar is that U.S. and Afghan troops will establish joint outposts in the city’s 17 precincts and surrounding areas, so that the population feels safe enough to attend the shuras, or councils. The Taliban has responded with a wave of assassinations, and Lt. Gen. David Rodriguez, who is Petraeus’ deputy, said the offensive will succeed only if local leaders “take risks” and brave the intimidation. That’s a lot to ask of people who mistrust both America and the Karzai government, and it may be the weakest link in the U.S. plan.

Obama’s goal is to gradually transfer responsibility to the Afghans so the U.S. can begin withdrawing troops next July. “They’ve still got a long way to go,” Gates told me. “I’m not saying that we’re near victory, or we’ve turned the corner, or that we’re now in a straight-line projection to get this done.”

The reason to be encouraged, Gates said, was that with the U.S. troop surge nearly complete, “we’ve got the pieces in place.”

David Ignatius is a Washington Post columnist. His e-mail address is davidignatius@washpost.com.