Nothing teaches skepticism of the advice of military leaders like the experience of warfare. President Lincoln discovered it. Roosevelt did too. So did Truman, Kennedy and Johnson. It was not unpatriotic for them to challenge their generals. On the contrary, by the end of World War II, an entire generation, well-versed in the fallibility of their commanders, sought out government officials who wouldn't hesitate to challenge them.

Recently, in the United States, a different phenomenon has been in play. It is considered almost sacrilege to publicly question the top brass. "Trust the generals" is almost a mantra among the current crop of Republican candidates for commander-in-chief (with the notable exception of the sporadically acute Ron Paul, who seems to have a somewhat firmer grasp on the concept of the chain of command and the reason for civilian leadership of our defense establishment).

Some of this reflexive deference is no doubt a product of genuine respect. But some is a product of the post-9/11 outbreak of jingoism that has distorted U.S. political debate and national security thinking for the past decade.

Generals and admirals are, of course, a diverse lot and the U.S. is fortunate to have some leading our military who are not only among their profession's best worldwide but who are also among the first tier of all public servants anywhere. But some are, naturally, not up to snuff, and furthermore, the military, like other branches of government, is susceptible to group think and to rendering decisions too colored by their own culture or self-interests.

With this in mind, it is fascinating how little critical assessment of the judgment and actions of the U.S. military in Iraq, Afghanistan, and Libya has taken place during the past ten years. While the military themselves have clearly acknowledged fundamental errors on the part of their leaders -- surges in both Iraq and Afghanistan reflected prior misreadings of the challenges on the ground and were course-corrections designed to adjust appropriately -- the public has not.

Almost robotically, we have assumed the generals know best, and the result has been two protracted, extremely costly, frustrating conflicts in which many of our most important goals have eluded us. Osama is gone, although getting him took far longer than many had hoped or expected. Saddam is gone. But so too are thousands of soldiers who went into battle with the wrong equipment and the wrong strategies. (The mistake of going after Saddam in the first place was an error by civilian leaders). Also gone are trillions of dollars that were spent upon the advice of military leaders who said they were essential to achieving levels of stability and reductions in threats that could actually never sustainably be attained. Did the military buy into unachievable goals? Or were those goals forced on them? Perhaps, but they also bought into them and ultimately became the advocates of ever-longer stays in the war zones.

While the sacrifice of the military must always be honored and while our military is certainly the best in the world, the military's leadership is simply wrong if they think that staying longer in Afghanistan will produce notably different medium or long term outcomes than departing sooner. The distinction between having the bulk of our troops out closer to 2012 or 2014 may result in slightly different situations on the ground or slightly greater capabilities for the Afghan security forces when the departure ultimately does come. But in the end, a longer stay will not fundamentally change the character of the country, the people, the government, the culture or the other factors that will relentlessly wear away at the changes we have worked so hard to achieve.

It does no disrespect to the generals to challenge their conclusions, especially when their advice over the past several years has produced such mixed results. On the contrary, it is disrespectful to the system within which they work and to the public they serve not to carefully challenge viewpoints -- whatever their origins -- that put so many of our soldiers, sailors, and airmen at risk. If anything, President Obama should do so more actively and openly going forward. He and his advisors are paid to know best, and to have and embrace ultimate responsibility for the long term interests of the U.S.

The majority of the American people are not always right either. But on Afghanistan, they are. According to a new poll, they feel that we should get out as fast as we can.  Not only do they have it right whereas the military leaders suggesting a slower withdrawal have it wrong ... but with some luck, this break between the two may be seen as something even more significant and promising: a return to a healthier willingness to question the chiefs at the Pentagon in ways in which the United States' great war leaders throughout history would find both comfortable and essential.

In a related development, perhaps having Leon Panetta, a former budget director and budget committee chairman, take office as new secretary of defense whose job will clearly be to help reduce spending and roll back the bloated military establishment is another positive sign in the same general direction. In fact, perhaps, after the Osama raid, with the beginning of the drawdown in Afghanistan, we are at a pivot point, the end of The Decade of 9/11 and the beginning of something new and more rational.