In war, it’s usually reasonably clear who the enemy is but for the American and NATO troops fighting in Afghanistan that’s not always the way it is. Of course, very little about the long slog of a war in Afghanistan is clear.

In August alone, Afghan troops being trained to defend their own country turned their weapons on their teachers 32 times. In all, 45 NATO soldiers have been killed by their Afghan colleagues this year. It’s bad enough to be killed by the enemy; it’s far worse (for the victims’ survivors, too) to die at the hands of an ally standing next to you.

That’s why the senior commander for special operations forces in Afghanistan has wisely, if reluctantly, suspended training for these new Afghan recruits until the more than 27,000 of them, supposedly working in partnership with his command, can be more closely examined for possible ties to the brutal Taliban insurgency.

The struggle to put an end to the attacks on their own forces by their supposed allies has vexed NATO officials, who nevertheless have conceded that many of the shootings might have been prevented had only existing security measures been properly applied. They acknowledge that numerous guidelines were not followed by both Afghans and Americans because there were worries that full compliance with the guidelines might impede the urgently needed growth of the Afghan army and police.

Remember, the United States and NATO are determined to leave Afghanistan by the end of 2014 and therefore it is imperative that they leave behind a fully trained force of Afghan soldiers and police. But increasingly it seems doubtful that is really possible.

According to press reports, special operations officials argue that the current process for vetting recruits is actually effective but they blame a lack of follow-up for allowing Afghan troops who developed sympathies for the insurgency or who became disillusioned with the Afghan government to remain as part of the program. But, as one senior special operations official said, “we’re living with the Afghans (so) we can’t afford to take chances with vetting.”

“Everyone admits there was a lot of international pressure to grow these forces, and the vetting of these individuals was cast aside as an inhibitor,” one American official told The Washington Post. The move to suspend the training of new recruits followed the Aug. 17 shooting of two American special forces members by a new Afghan local police recruit in sparsely populated western Afghanistan.

The local police project puts special forces teams in remote villages where they work with local elders and government officials to help villagers defend themselves against insurgent attacks and intimidation. The program involves about 16,000 Afghans and is viewed by Allied commanders as a critical way to spread security and the influence of the Afghan government to parts of Afghanistan where the Taliban enjoy relative security.

Meanwhile, the American public can only continue to wonder what the outcome in Afghanistan will ultimately look like. The United States and its NATO allies have no reason or desire to occupy that far-away (both geographically and culturally) country, and yet there’s very little reason to have faith in the fragile and corruption-tolerant government that would be left in charge in Kabul.

Afghanistan has not been a major issue in this year’s presidential election campaign, perhaps because nobody has a better idea than President Obama’s goal of bringing our troops home by the end of 2014. Americans can only hope that between now and then our allies are no longer the enemy.