As Gen. David Petraeus kicks off an extended media blitz intended to make Americans feel better about the war in Afghanistan -- or at least give him some more time to fight it -- he faces a foe more implacable than al Qaeda, or even the Taliban: Reality.

That reality, increasingly obvious to national security experts and the general public alike, is that no amount of good intentions or firepower is going to advance our fundamental interests in Afghanistan -- and that as much as Petraeus might be able to achieve in the next six months, or a year, little to none of it is sustainable and most of it is, even worse, counterproductive.

U.S. taxpayers are spending vast amounts of money on the war -- over $200 million a day for military operations alone. Our troops work tirelessly, fight and die to protect and build up the people and institutions of Afghanistan.

But how that turns into success remains wildly unclear. And even more importantly, the relationship between what we're doing on a day to day basis and our ostensible goal -- keeping America safe from al Qaeda -- seems increasingly tenuous.

In the first of many planned interviews, Petraeus will tell NBC's David Gregory on "Meet the Press" on Sunday that his intention is "to show those in Washington that there is progress being made" and to persuade decision-makers "that we've got to build on the progress that has been established so far."

But what Petraeus can't do is say with any confidence that this "progress" can be sustained. Nor can he connect it to an actual threat to our national security.

By contrast, in a reflection of an emerging new consensus in the national security community, a self-styled "Team B" on Afghanistan strategy is advocating much narrower goals and reduced military commitment in the region.

According to an advance copy of the group's forthcoming report, "the war in Afghanistan has reached a critical crossroads. Our current path promises to have limited impact on the civil war while taking more American lives and contributing to skyrocketing taxpayer debt. We conclude that a fundamentally new direction is needed."

The report represents the views of about 40 influential national security figures from academia, think tanks and the business community. Organizer Steve Clemons of the New America Foundation said the group is varied in its makeup, but unified by its doubts about the current course.

Its survey of the landscape concludes: "We are mired in a civil war in Afghanistan and are struggling to establish an effective central government in a country that has long been fragmented and decentralized. No matter how desirable this objective might be in the abstract, it is not essential to U.S. security and it is not a goal for which the U.S. military is well suited. There is no clear definition of what would comprise 'success' in this endeavor, and creating a unified Afghan state would require committing many more American lives and hundreds of billions of additional U.S. dollars for many years to come."

"General Petraeus is a smart man and he attracts smart people and I know that since he's been given this onerous duty, he's been looking at at least tactical and operational shifts," said Patrick Cronin, a South Asian expert at the Center for a New American Security and one of the contributors to the report. "But what he isn't addressing is the need for a new political strategy."

Cronin said Petraeus's target audience "shouldn't buy into this military incrementalism. 'Six months more' is not a strategy."

Brian Katulis, a national security expert at the Center for American Progress, said he is worried that members of the Obama administration have lost sight of what he calls the fundamental question: "Are we actually keeping Americans safe?"

"Are we actually preventing people from flying planes into our buildings?"

"Some of the most striking arguments for continuing the conflict are actually sunk costs and national pride and honor," Katulis said. We keep going because "we've spent so much and it would be such an awful thing not to justify the costs and lives."

The war's goal at this point seems to be establishing overall stability in the country. But among the many other problems, Katulis said, there's no good way to measure that; officers on the ground are reduced to tallying things like the number of stores open at night, or the number of shoppers at a market.

That sort of metric leads Katulis and other national security experts to wonder: What does that have to do with the security of our own country? And to the extent that it does, is it really the best use of our resources? What about the threats to our homeland developing in other parts of the world?

Cronin said Petraeus should be forced to explain not just what he intends to do, but how it can be sustained. If he drives the Taliban out of one region -- "if we do sacrifice those lives to do that" -- it still "doesn't put us on a sustainable glidepath," he said.

"Petraeus wants to buy more time, because he needs time to demonstrate that what he's doing can have a positive effect," Cronin said. "But it doesn't have a large enough positive effect, and it's too costly in terms of blood and treasure."

"Yes, there are different views of this war," he added, "but if you look at enough of the evidence, you can't be sanguine that we are indeed winning hearts and minds" -- which is a critical goal of Petraeus's counter-insurgency strategy. In fact, Cronin said, the evidence suggests that we are making ourselves "even less popular than the Taliban... we are making them stronger, and what we're doing is not effective enough."

With al Qaeda essentially gone from Afghanistan, "the original purpose has largely dissipated," Cronin said. "This strategy is actually being counterproductive for our interests."

Katulis also notes that the administration's plan still lacks a clear, positive goal. "If you go through all of the senior administration officials' talking points, they often define the goal as a negative."

The most senior administration official is fond of saying things like: "I've set a clear and achievable mission -- to disrupt, dismantle and defeat al Qaeda and its extremist allies and prevent their return"

But, said Katulis, "that doesn't actually tell us what it is we actually have to leave behind."

Petraeus is said the be starting to hedge on President Obama's promised deadline of July 2011 for withdrawing American troops.

That's hardly surprising. As I reported two weeks ago, the timeline for an American troop withdrawal has steadily been growing longer for some time, with Obama's deadline looking more and more hollow, and the real timeline for significant troop withdrawal -- barring a change in course -- now extending at least to 2014, if not far beyond.

But from Cronin's perspective, Obama had a year to turn things around, and it's already over. "That's enough empirical evidence to know if there is something that can be salvaged here," he said.

Cronin said the "Team B" solution is "something in between what we've been doing and complete abandonment. It's not that it's a guarantee of success, but we've got to recognize that what we're doing now is not succeeding, either."

Cronin said U.S. national security does not depend on the military defeat of the Taliban, or on a strong central government. The plan instead calls for power-sharing, and for a smaller military presence that focuses on keeping al Qaeda at bay.

So if it's increasingly clear outside the military and the executive branch that a radical reassessment of the war is necessary, why isn't it clear inside?

"If there's one thing that drives the current officer corps in our military it's that they want to avoid the sense of a loss, and perception of another Vietnam," Katulis said.

As for inside the White House, "there's the political and rhetorical box that they themselves have set," Katulis said.

It's also possible that Obama is thinking things he just can't say out loud.

"Our Afghan partners are just not up to the task of what we would like to see," said Cronin. "You can't say that as a government when you're knee deep in a war. But at the end of the day, you have to be realistic about U.S. interests."

And as long as the war is being fought, "the president can't afford to look incoherent on this," Cronin said. "This president in particular, because he'll be attacked from the right, has to look strong on this issue."

Obama "can't afford to have Joe Biden and others leading an ongoing critique of the war" which is why he "put a lid on that last year," Cronin said. Nevertheless, "I think the reality is that inside the administration there continue to be serious people with serious doubts about where this is heading."

But there's yet another force preventing Obama from pivoting, according to Katulis: The possibility that, after he reduces the military footprint in Afghanistan, someone from that country then comes to the U.S. and commits and act of terror.

Staying in Afghanistan for that reason, however, is strikingly reminiscent of former Vice President Cheney's notorious "One Percent Doctrine," as described in the Ron Suskind book by that name. Cheney's basic view was that if there's even a one percent threat of a "high-impact" terrorist event, then the government should respond as if it were a certainty. That led to a lot of overkill.

Cronin said he thinks the president doesn't have much choice. "I think there are fewer and fewer people who are willing to give just a blank check for what's going on," he said.

And Cronin said he thinks Obama "can find a way to make this politically more palatable" by following through with his promised July 2011 drawdown, continuing to make the case for a pivot toward a more diplomatic, less military-intensive strategy. And he can make the case that "there are plenty of other threats out in the world that we're ignoring because of this."

Afghanistan is overkill in the wrong place, Katulis said. "We're really running a risk of having a national security strategy that is not in balance globally."